
Free Printable: Low Carb & Keto Food List
Get It NowThis post may contain affiliate links, which help keep this content free. (Full disclosure)
- Why You’ll Love This Keto Peanut Butter Fudge Recipe
- Sugar-Free Peanut Butter Fudge Ingredients
- How To Make Keto Peanut Butter Fudge
- Variations
- How Many Carbs Are In Peanut Butter Fudge?
- Storage Instructions
- More Keto Peanut Butter Dessert Recipes
- Tools To Make Easy Sugar-Free Peanut Butter Fudge
- Keto Peanut Butter Fudge Recipe (4 Ingredients)
If you’re a peanut butter lover like me, you have to try this sugar-free keto peanut butter fudge recipe. The taste and texture is spot on, you need just a few ingredients, and you won’t be able to tell the difference at all between this and regular old-fashioned peanut butter fudge with powdered sugar.
Nobody likes gritty fudge, so using a keto powdered sweetener is so important! This recipe relies on Besti Powdered Monk Fruit Allulose Blend because it tastes just like sugar, dissolves easily into the fudge base, and clocks in at zero grams net carbs.
Why You’ll Love This Keto Peanut Butter Fudge Recipe
- Sweet peanut butter flavor
- Silky smooth, fudgy texture
- Preps in just 10 minutes
- Only 3 grams net carbs in a large serving (or less than 1 gram for 1-inch squares!)
- Protein-rich snack

Sugar-Free Peanut Butter Fudge Ingredients
This section explains how to choose the best ingredients for peanut butter keto fudge, what each one does in the recipe, and substitution options. For measurements, see the recipe card below.
- Peanut Butter – Make sure it’s salted and has no added sugar (check labels!). Also, for the fudge to set, it’s important that it’s the thick, creamy kind, not the runny kind. Many brands labeled “natural peanut butter” are too runny for this recipe. I like this brand, which is thick and creamy.
- Butter – I prefer grass fed butter for best flavor and nutrition, but you can use any unsalted butter. If you use an unsalted peanut butter, then your butter should be salted instead.
- Besti Powdered Monk Fruit Allulose Blend – Not only does it taste and act like powdered sugar, it also dissolves easily (unlike other keto sweeteners), for a completely smooth fudge texture. If you have to replace this with a different sweetener, make sure it’s powdered, but keep in mind that powdered erythritol based sweeteners (including most other brands of stevia and monk fruit) may crystallize when storing and create a gritty texture.
- Protein Powder – I used collagen (this brand is great!), but any neutral protein powder should work for sugar-free peanut butter fudge. Be sure it’s unsweetened.
- Vanilla Extract – Optional, but recommended for flavor. You can also use different extracts here to change it up.

How To Make Keto Peanut Butter Fudge
This section shows how to make sugar-free peanut butter fudge with step-by-step photos and details about the technique. For full instructions, see the recipe card below.
- Prep the pan. Line an 8×8 pan with parchment paper or wax paper, letting the paper hang over the sides.
- Melt peanut butter and butter. In a large mixing bowl, heat peanut butter and butter in the microwave, or in a sauce pan on the stove over low to medium heat, until melted.


- Mix keto friendly peanut butter fudge. Stir in Besti Monk Fruit Allulose Blend and collagen powder, until smooth. Taste and adjust sweetener to taste. Remove from heat and stir in vanilla.
- Freeze. Pour the mixture into the lined pan and freeze until firm. (You can also chill in the fridge instead, but the fudge will be more soft.)
TIP: Add toppings before chilling if you like. See variation ideas below!


- Slice. Lift the parchment paper out of pan and place fudge onto a cutting board. Slice into squares.

TIP: A warm, wet knife slices more easily.
Run the knife under hot water before slicing, and anytime you notice sticking.

Variations
- Double peanut – Sprinkle some chopped peanuts over the top, or fold into the batter.
- Chocolate chip – Fold sugar-free dark chocolate chips into the batter before chilling, or simply sprinkle on top.
- Buckeye – After making the peanut butter layer, make keto chocolate fudge and pour that over the peanut butter before chilling. (You can also make individual keto buckeyes like this instead.)
- White chocolate – Melt 1/2 cup sugar-free white chocolate chips and stir into the fudge batter.
- Maple walnut – Replace 2-3 tablespoons of the peanut butter with keto maple syrup. Add 2-3 more tablespoons of collagen and 1/3 cup chopped walnuts.
- Sea salt – Sprinkle flaky sea salt over the fudge before freezing.
If you prefer more classic fudge recipes, try my keto chocolate fudge, or if you like the kind made with condensed milk, I have a sugar-free version in my Easy Keto Carboholics’ Cookbook.
How Many Carbs Are In Peanut Butter Fudge?
Traditional peanut butter fudge has about 16 grams carbs per 1-inch piece. Instead, this sugar-free peanut butter fudge recipe has just 3 grams net carbs in a 2×2-inch piece (that’s 4 times the serving size!). If you cut the fudge into 1-inch pieces, each one will have less than 1 net carb.
Storage Instructions
Store the sliced keto peanut butter fudge bars in an airtight container in the freezer. Soften on the counter for a few minutes before serving. (They are also okay in the refrigerator, but will be softer and harder to handle.)

More Keto Peanut Butter Dessert Recipes
If you like this low carb peanut butter fudge recipe, you might also like some of these other keto peanut butter recipes:
- Keto Chocolate Peanut Butter Cheesecake
- Chocolate Peanut Butter Fat Bombs
- Keto Peanut Butter Pie
- Sugar-Free Peanut Butter Cups
- Keto Peanut Butter Cookies
Tools To Make Easy Sugar-Free Peanut Butter Fudge
- Baking Pan – These pans hold up well and are made in the US. This one is the perfect size for this keto pb fudge recipe.
- Glass Storage Containers – Store any leftover sugar-free fudge in these airtight containers.
Keto Peanut Butter Fudge Recipe
Reader Favorite Recipes
The recipe card is below! Readers that made this also viewed these recipes:
Keto Peanut Butter Fudge Recipe (4 Ingredients)
This sugar-free keto peanut butter fudge recipe is rich, fudgy, and easy to make with just 4 ingredients. Naturally gluten-free, with a dairy-free option.
Recipe Video
Tap on the image below to watch the video.Like this video? Subscribe to my YouTube cooking channel for healthy recipes weekly! (Click the bell icon to be notified when I post a new video.)
Ingredients
Tap underlined ingredients to see where to get them. Please turn Safari reader mode OFF to view ingredients.

Get Keto Sweetener For This Recipe
GET BESTIInstructions
Tap on the times in the instructions below to start a kitchen timer while you cook.
-
Line an 8×8 in (20×20 cm) baking pan with parchment paper, letting it hang over the sides. Set aside.
-
Combine the peanut butter and butter in a large bowl (if using the microwave) or saucepan (if using the stove). Heat over low heat, stirring a few times, until melted and smooth.
-
Stir in the sweetener and collagen powder, until smooth. Taste and adjust sweetener if needed. Remove from heat. Stir in vanilla extract.
-
Spread the mixture into the baking pan. Freeze for 30-45 minutes, until firm.
-
To slice, lift the parchment paper out of the pan and place on a cutting board. Run a knife under hot water to warm it up, dry, and use it to cut the fudge into squares. Store in the freezer. If desired, soften on the counter for a couple of minutes when serving.
Last Step: Leave A Rating!
Share your recipe picture by tagging @wholesomeyum and hashtag it #wholesomeyum on Instagram, or in our Facebook support group, too – I’d love to see it!
Recipe Notes
Serving size: 1 2×2″ square
This sugar-free peanut butter fudge is very filling. If you want to enjoy it as a bite size treat with fewer carbs and calories, just cut it into smaller squares.
Nutrition facts are provided as a courtesy. Have questions about calculations or why you got a different result? Please see our nutrition policy.
Want to save this recipe?
Create a free account to save your favorite recipes!
Sign Up To Save Recipes© Copyright Maya Krampf for Wholesome Yum. Please DO NOT SCREENSHOT OR COPY/PASTE recipes to social media or websites. We’d LOVE for you to share a link with photo instead. 🙂

79 Comments
Bella
I made it without the protein powder the first time and it was AMAZING. So creamy amd satisfying. I found that the protein powder made the texture a little less pleasant and the taste a kind of dry but still yummy overall😁👍
Barbara Fontaine
Can you use super sweet sugar from thin and healthy mama instead of monk fruit?
Wholesome Yum D
Hi Barbara, I have never used anything from that brand but I only recommend Besti because it dissolves just like real powdered sugar and has no aftertaste.
Jamie
Very easy to make and is the perfect little treat without the guilt. I cut them and have them in a ziplock bag in the freezer, really yummy, taste like peanut butter m&m’s
Melissa
Can brown sugar Swerve be used in lieu of the monk fruit?
Maya | Wholesome Yum
Hi Melissa, I don’t recommend Swerve for fudge because erythritol-based sweeteners (including Swerve) tend to turn out gritty and crystallize. If you want to use a brown sugar replacement, try Besti Brown instead, which dissolves easily and will yield a smooth result.
Nancy Secaur
My hubby just said, “that fudge is REALLY good!” I goofed & used the larger measure on the collagen powder, then scooped out what I could, but it still had to have been 1/2 cup instead of 1/4. Couldn’t tell, though. It isn’t the same as grandma-in-law’s, but it’s sure a darned good fudge, and the biggest issue is stooping at one serving!
Lisa
Could I use PB Powder in place of the Collagen?
Wholesome Yum D
Hi Lisa, I think that should work for you but I have never tried it. Please let me know the results if you try this out!
Bernice
I’m already looking forward to making this fudge again. My husband just loved it.
Krissy Allori
I’ve been looking for a way to make peanut butter fudge without sugar and I’m so glad I found this recipe! Turned out great!!!
Abigial
I love some good peanut butter fudge, and this recipe makes me feel better with the addition of the protein powder! Thank you so much for sharing this recipe!
Heather Rose
This is by far the best fudge recipe out there! Love it!
Herbert
Maya … I have made this a gazillion times lol. I keep it in my fridge at all times. Figured I should give credit where due. By far my favorite pb snack!!! Thanks for all you do
Kristen
Fiancé is diabetic and has been really wanting peanut butter fudge and he was over the moon about this recipe.
Amy
Absolutely amazing!
DONNA NICHOLS
hi, this recipe looks great, but I cannot afford to spend almost just on the powder that is listed just wondering if there is something else to use as a substitute?
Wholesome Yum M
Hi Donna, You can omit the protien powder from the recipe.
Andrew
Does it have to always be frozen or can you leave it at room temperature for longer than a few minutes?
Wholesome Yum M
Hi Andrew, This recipe will always need to be kept cold. As the fudge warms up it will become soft and gooey.
Mark
If I wanted to use Sugar-Free PB Fit (Peanut Butter Powder) what adjustments would I need to make
Wholesome Yum M
Hi Mark, No alternations are necessary. Just be sure to reconstitute your peanut butter powder with water before using in the recipe.
Betsy
Yum. I made this using smuckers natural peanut butter, honey badger collagen powder, lakantos powdered sweetener. Came out good. Will make again. Cut into about 72 small pc as I would like a nibble every now and then, not a huge pc.
elaine
This peanut butter fudge is keto heaven. Thank you so much. Maybe its just too good!!
Its creamy has no after taste whatsoever and i think it may be my downfall.
Jessica
This is my new favorite! Almost too good!
Jessica
Flavor turned out great! I used unflavored protein powder and nutty PB because that’s what I had.
Dawn
These are fabulous! I used Isopure unflavored Protein Powder and Santa Cruz peanut butter. It was perfect! My go to Keto Peanut Butter Fudge!
Karen
This is another delicious recipe! I didn’t have any protein powder, so used almond flour in place of it and it turned out amazing!!
Chris
This is AWESOME. Super easy to make and super delicious. I made it exactly as the recipe specified, except halved (and used a smaller dish). Also added a few Lily’s semi-sweet choc chips the second time. Thank you for sharing the recipe.
Shirley
From your comments below, are you saying that you DO have to use a protein powder for the structure of the fudge, but you DO NOT have to use a collagen powder? Does this mean that you can’t use collagen powder alone? Thanks.
Wholesome Yum M
Hi Shirley, This recipe really turns out best with the addition of either a powdered protein or collagen powder. Whatever you have on hand should work fine. It helps to provide structure to the recipe.
Holli Krebs
Thank you so much for your recipes. Do you know the difference it would make to use either protein powder or egg white powder? Thank you!
Wholesome Yum M
Hi Holli, You can use protein powder in place of the collagen. It will still turn out great! Enjoy!
Tom West
I use ice cube trays …. nice size for me
Stephanie K Molsbee
Can you substitute gelatin for the collagen? If so, is it the same amount or different?
Wholesome Yum M
Hi Stephanie, If you don’t have collagen on hand, then you can leave it out. Gelatin will not work in this recipe. The recipe will still fine work without collagen.
Betsy
Made this tonight, 1 serving, (scaled it down). Used isopure protein powder in place of the collagen. Used extra crunchy Teddy brand peanut butter and followed recipe as written. Yummmy. Hubby was very happy to as we share this 1 serving to make sure we like it. Definitely helps with the peanut butter craving.
Mary
Just made this! It is SO good! Thinking I was going to have to live without peanut butter fudge was just heartbreaking! Thank you so much for sharing this recipe! I am so glad I decided to give it a go! No doing without peanut butter fudge here now!
Betsy
Can I use isopure unflavored protein powder?
Wholesome Yum M
Hi Betsy, I think that should work. Using protein powder might give a slightly powdery texture compared to collagen peptides (which dissolve completely in liquids and foods) but I think it will still work out well.
Ana
How much salt would you add if you don’t have salted peanut butter?
Wholesome Yum M
Hi Ana, I would start with 1/2 teaspoon and then adjust to taste.
Dawn Yutzy
This is utterly amazing! It hit the spot and it’s great with tea for a bedtime snack!
Nina
Oh my gosh, this is the first keto snack that I’ve made and love it! No weird after taste, just perfect. Followed the measurements to the letter and substitute the vanilla for maple flavoring and added pecans. The smell reminded me of bit-o-honey. So satisfying.
Thank you
Alpa Modhera
Hello
Can you substitute protein collagan peptides for the protein powder?
Maya | Wholesome Yum
Hi Alpa, Yes, you can!
Josie
Absolutely perfect recipe as written! I make this at least twice a month and keep it in the freezer. The fam loves it! I use chunky, organic unsweetened PB. Thank you so much!
Amita
Hi, can you substitute almond butter?
Maya | Wholesome Yum
Hi Amita, Yes, you can!
Jeff
Can Keto recipes be doubled from 8×8 to a 9×13 pan size? And if a recipe calls for peanut butter, can powdered PB be used? Thanks tons.
Maya | Wholesome Yum
Hi Jeff, Yes, you can double it. I don’t recommend powdered peanut butter for this recipe, though.
Pamela
OMG!! I am in peanut butter fudge heaven!! This recipe is AMAZING! I added a few pecans in it. Thanks so much for this recipe!!! I LOVE IT!
Maya | Wholesome Yum
I love that you added pecans, Pamela!
Renuka
Hi Maya, This recipe and the feedback makes it sound like a winner. Can’t wait to try it. But I’m vegetarian. What can I use in place of the collagen?
Maya | Wholesome Yum
Hi Renuka, Another protein powder, like egg white protein powder or pea protein powder should work.
Jana
Can I use Great Lakes collagen?
Maya | Wholesome Yum
Hi Jana, I didn’t test with that brand but I’m sure you can.
Phil
Can’t use natural peanut butter, too loose.
Maya | Wholesome Yum
Hi Phil, Did you try the recipe? I used natural peanut butter without a problem.
CM
Made this, we used Dr Axe multi collagen and creamy organic peanut butter , used swerve confectioners. It had great flavor but is grainy in texture. What are we doing wrong?
Wholesome Yum M
Hi CM, Sorry this recipe didn’t turn out as expected. I can’t speak for other sweeteners, but Wholesome Yum Powdered Erythritol is powdered very fine and doesn’t leave a gritty texture in this recipe.
Carol Stackhouse
Thank you so much!
Maya | Wholesome Yum
You are welcome, Carol! Thanks for stopping by!
Stacy
This is wonderful fudge! We all love it!
Maya | Wholesome Yum
Thank you, Stacy!
Tara
Thanks for sharing this recipe. Peanut butter fudge is near and dear to my heart as I have been making an old family recipe for years. With going keto, I have been thinking about how to convert the recipe to a low sugar version. I would like to figure out a way to get it to set up without freezing it. Thanks for turning me onto collagen.
Maya | Wholesome Yum
Thank you, Tara! I’m glad you can enjoy this recipe!
Diane
So good. I make a batch to have in the freezer at all times. Sometimes smooth PB sometimes chunky. This recipe is perfect!
Maya | Wholesome Yum
Thank you, Diane!
Gloria
Do you have to use a protein powder or can you skip this ingredient?
Maya | Wholesome Yum
Hi Gloria, You need the protein powder. It provides structure.
Victoria
Does it have to be collagen protein powder? Or can regular protein powder suffice?
Maya | Wholesome Yum
Any kind will work, I just like the benefits of collagen.
Brittany
Can you use any collagen powder?
Maya | Wholesome Yum
Hi Brittany, Yes, you can.
Brittany
These are SO GOOD and it was SO EASY. Definitely one of my favorite keto recipes. This one will be staying in frequent rotation.
Maya | Wholesome Yum
Thank you, Brittany!
Cristina Kadonsky
Can I use another powder and which one? I don’t have a collagen one and this looks so great!
Maya | Wholesome Yum
Hi Cristina, I haven’t tried it with a different protein powder, but think it should work fine. I hope you’ll try the collagen sometime – you can get it from the link on the recipe card.