Baked Easy Cheesy Zucchini Casserole Recipe (Zucchini Gratin)

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If you’re drowning in zucchini, an easy zucchini gratin recipe is the perfect way to use up a good amount. This low carb cheesy zucchini casserole requires three medium zucchini in a 1 1/2 quart casserole dish, but you can easily double (or even triple!) the recipe to make more in a larger pan!

As we head into August, I know I’m not the only one with more zucchini than I know what to do with. Anyone with a garden will say that right now!

I keep meaning to start a garden, but never have the time. One of these years I’ll take the plunge.

For now, despite no garden, I still have a zucchini problem. It’s my own fault, too. I just couldn’t resist buying way too much at the farmers’ market.

It’s a good thing my family loves zucchini as much as I do. All the more reason to make cheesy zucchini au gratin, right?

The only thing is, I struggled with the name for this dish. Cheesy zucchini gratin? Low carb zucchini casserole? Healthy zucchini bake? I couldn’t decide, so I’m using the names interchangeably.

An Easy Zucchini Casserole Recipe for Zucchini Week

Fortunately, it’s Zucchini Week here at Wholesome Yum, so I have lots of ways to use up all my zucchini! So far, I’ve made zucchini pizza bites, fried zucchini & squash, and zucchini noodle salad with bacon and tomatoes. I can’t even decide which one I like best.

My whole family is loving Zucchini Week. There aren’t many foods that are awesome enough to want to eat every day for a week. This is one of the few.

Zucchini is naturally low carb, keto friendly, gluten-free, and everyone loves it even if they aren’t following any of those special diets. In the middle of the summer, give me all the zucchini!

Low carb zucchini gratin is yet another way I’m using zucchini this week. With a delicious creamy brie sauce, cheesy Swiss Gruyere topping, Italian seasoning, and summer zucchini (of course!), you can’t go wrong. It’s the ultimate comfort food.

Cheesy low carb casseroles like this one are my favorite kind. If you’re a fan of them too, you’ll want to check out my brussels sprouts casserole au gratin, pesto chicken bake and low carb cauliflower casserole. This easy broccoli cheese soup is one of the most popular! Can’t forget to add this cheesy zucchini casserole to the list!

Ways To Make Low Carb Zucchini Casserole

There are multiple ways that people make baked zucchini casserole recipes. Many of them shred the zucchini first, or they cook it in some way separately, to get rid of the moisture.

I’d like to try a shredded zucchini casserole sometime, but I thought a sliced zucchini gratin was actually a much faster way to make an easy zucchini casserole. And you probably know by now – I am all about easy!

That’s why I think you’re going to love how quick it is to prepare this cheesy zucchini gratin bake. The active prep time is only then minutes!

The “hardest” part is impatiently waiting for the sliced zucchini to drain in the beginning. (Patience is not my strong suit. I commend anyone that’s good at it.) But, you can go off and do something else while this is happening.

Ingredients for Easy Zucchini Gratin

This low carb zucchini gratin recipe uses common ingredients that I often have around. During the summer months, it’s pretty typical for me to create easy zucchini recipes on a whim. And, the most common themes are cheese (lots of cheese!) and random ingredients I find in the fridge. This was one of those!

The ingredients needed are zucchini (obviously!), sea salt, black pepper, brie cheese, heavy cream, almond milk, butter, garlic, sharp shredded cheese, and Italian seasoning. Okay, so that list is not as short as my five-ingredient recipes. But, these are all simple ingredients you can find at your local grocery store.

I recommend using brie in the sauce as written, because it creates a super creamy consistency. It thickens it very nicely, too!

As for the cheesy zucchini casserole topping, feel free to swap any shredded cheese you like. I used a blend of Swiss and Gruyere for lots of depth and flavor. Cheddar would be delicious, too!

The Key to the Best Zucchini Casserole Recipe

The key to the best zucchini casserole recipe is making sure that it isn’t too watery. Zucchini is a very “wet” vegetable, and baking it in a casserole dish releases a lot of moisture. This is even more true when you are not using a starch, like flour. So, it’s important to take that into account when making gluten-free zucchini casserole recipes.

This is why the draining step is so important. Please, please don’t skip it! It prevents the low carb zucchini casserole from becoming a watery mess. Sprinkling the slices with salt first helps them drain better, so that is why we do that first.

While the zucchini drains over the sink, you can use the passive time to make your main dish. I think it goes very well with pesto stuffed chicken. Both are filled with Italian flavors. (Or, get out of the kitchen and spend some time outside!)

Once the zucchini is done draining, the rest of the steps are quick and easy. Just ten minutes prep, remember?

How To Make Zucchini Casserole

Preheat the oven to 400 while you prepare the zucchini casserole. Arrange the zucchini slices in overlapping rows in a small casserole dish, and season them with black pepper. I like to use a stoneware dish like this one.

Next, heat the brie, cream, milk, butter, and garlic in a small saucepan, until everything is nice and smooth. Here is the cheese sauce for your zucchini casserole! Don’t be surprised if it’s a little thin – it will thicken more in the oven later.

Pour the sauce over the zucchini, and top with plenty of shredded cheese. (In case you couldn’t tell, this is the ultimate cheese lover’s zucchini side dish!)

Don’t forget the Italian seasoning on top. If you have other herbs or spices around, feel free to use those instead. This zucchini gratin recipe is quite versatile! In fact, if you happen to make this dish later on in the fall, it would be delicious with some fresh rosemary, too.

Stick your cheesy zucchini casserole into the oven for about half an hour, until it’s golden brown. You’ll know it’s done when the zucchini is soft, the cheese is browned, and the sauce is thick.

If the cheese browns but the sauce is too watery for some reason, you can still fix it. Cover the top (to prevent burning the cheese) and lower the oven temperature to 350 degrees. Then, continue baking for another 10 to 20 minutes, until the sauce thickens more.

That’s it – your zucchini au gratin is ready to serve! It’s simple, it’s delicious, and it’s definitely the best zucchini casserole in my book.

Baked Easy Cheesy Zucchini Casserole Recipe (Zucchini Gratin):
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Baked Easy Cheesy Zucchini Casserole Recipe (Zucchini Gratin)

This easy zucchini gratin recipe is a baked cheesy zucchini casserole that everyone will love! Healthy, low carb, gluten-free, and delicious. Only 10 minutes prep time & simple ingredients!

Course Side Dish

Cuisine American

Keyword casserole, gluten-free, keto, low carb, nut-free, sugar-free, vegetarian, zucchini

Calories 239 kcal

Prep Time 10 minutes

Cook Time 30 minutes

Total Time 1 hour 25 minutes

Author Maya Krampf from WholesomeYum.com

Servings 6 servings

Recipe Video

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Ingredients

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• 3 medium Zucchini (sliced in 1/4" thick slices)
• Sea salt
• Black pepper
• 1 1/2 cup Swiss Gruyere shredded cheese blend (or any shredded sharp cheese; divided)
• 3 oz Brie cheese (edges cut off)
• 1/3 cup Heavy cream
• 2 tbsp Unsweetened almond milk (or any milk of choice)
• 1 tbsp Butter
• 2 cloves Garlic (minced or crushed)
• 1/2 tbsp Italian seasoning

Instructions

RECIPE TIPS + VIDEO in the post above, nutrition info + recipe notes below!

Click on the times in the instructions below to start a kitchen timer while you cook.

1. Toss the zucchini slices with sea salt. Place into a colander and set over the sink to drain for 45 minutes. Pat dry at the end.

2. Preheat the oven to 400 degrees F (204 degrees C).

3. In a small 1.5 quart (1.5 L) casserole dish, arrange the zucchini slices in several overlapping rows, sprinkly very lightly with half of shredded cheese between rows. You'll use about 3/4 cup cheese total. Season lightly with black pepper. (They already have salt at this point.)

4. Combine the brie, cream, milk, butter, and garlic in a small saucepan. Heat for a few minutes on the stove over low to medium-low heat, stirring frequently, until the cheese melts and the mixture is smooth. If desired, add sea salt to taste. Pour the mixture evenly over the zucchini.

5. Sprinkle the remaining 3/4 cup shredded cheese blend on top. Top with Italian seasoning.

6. Bake for about 30-35 minutes, until the cheese on top is dark golden brown and the zucchini is soft.

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Recipe Notes

Serving size: 1/6 of entire pan

Video Showing How To Make Zucchini Gratin:

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Nutrition Information Per Serving

Nutrition Facts

Amount per serving. Serving size in recipe notes above.

Calories 239

Fat 19g

Protein 12g

Total Carbs 6g

Net Carbs 5g

Fiber 1g

Sugar 2g

Where does nutrition info come from? Nutrition facts are provided as a courtesy, sourced from the USDA Food Database. You can find individual ingredient carb counts we use in the Low Carb & Keto Food List. Carb count excludes sugar alcohols. Net carb count excludes both fiber and sugar alcohols, because these do not affect blood sugar in most people. We try to be accurate, but feel free to make your own calculations.

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If you want to know more about how to start a low carb diet, want to substitute sweeteners, need a food list, or need support, check these guides:

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Starter Guide Sweetener Conversion Calculator Keto Low Carb Macro Calculator Low Carb Keto Food List + Printable PDF

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