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Low carb casseroles are one of my favorite dinners, because they require making just one dish – instead of separate entrees and low carb side dishes. And during zucchini season, this low carb chicken zucchini casserole recipe is sure to become a favorite as a meal by itself. (Also try cheesy zucchini gratin if you want a zucchini casserole that’s a side dish only.)
If you’ve made a low carb zucchini casserole before and it turned out watery, don’t be so quick to dismiss this one. It’s not watery – promise! Besides, the Swiss Gruyere cheese sauce is amazing.
Tips For Low Carb Chicken Zucchini Casserole
The instructions for how to make low carb chicken zucchini casserole are below, but here I want to share some tips to make it perfect:
Save time by making the different parts in parallel.
You can cut zucchini while mushrooms and onions cook. Then later, you can make the Gruyere cheese sauce while the oven preheats. Speaking of the sauce, here is what it looks like when done, poured over the rest of the ingredients before mixing:
Cook the mushrooms and onions to desired doneness.
There is a range for how long to cook the mushrooms and onions for this chicken zucchini casserole recipe. Anything from translucent to caramelized is great!
There is a trade-off here between time and taste. At the very least, you want the mushrooms and onions to be firm and not crunchy.
If they aren’t soft, that means they still have liquid in them and this will make the casserole watery as it cooks. As long as they are soft, you can choose whether you want them to be translucent or cook for longer to get that amazing caramelized flavor.
Keep heat at medium-high when stir frying the zucchini.
Keeping heat on the higher side browns the zucchini and ensures that the liquid evaporates. And, browning the outside is delicious!
Don’t remove the zucchini from the stove too soon.
Similar to the last point, it’s important to make sure liquid evaporates from the zucchini. Cooking the zucchini to evaporate the liquid is the key to a low carb chicken zucchini casserole that isn’t watery.
Be careful not to overcook the chicken.
The amount of time needed will vary depending on the size of the chicken pieces. Since it’s a casserole, they should be bite-sized.
With pieces that small, they should be done once you see they have browned on the outside. Small pieces cook very quickly!
No need to waste time washing the saute pan between steps.
The chicken zucchini casserole recipe does require several saute steps, but you don’t really need to wash the pan in between. Wipe it lightly with a paper towel just to make sure there aren’t any pieces, and that should be enough.
How To Make Chicken Zucchini Casserole Ahead
One great thing about this low carb chicken zucchini casserole is that you can make it ahead. If you want to meal prep for the week, do all the steps except the final baking at the end. Store it in the fridge, then bake when ready to eat.
If you happen to be making shredded chicken as part of your meal prep, or you have some rotisserie chicken, you can use that in this recipe. Then you an skip the step of pan searing the chicken pieces and just throw the cooked chicken into the bowl.
You can also freeze chicken zucchini casserole! Even with the Gruyere cheese sauce, it works fine because it will be heated before serving.
To freeze, do the same as above with the fridge method above, but freeze instead. You can then bake from frozen for an effortless dinner anytime.
More Easy Cheesy Casseroles
- Chicken Bacon Ranch Casserole
- Cheesy Yellow Squash Casserole
- Chicken Cordon Bleu Casserole
- Mexican Ground Beef Casserole
- Loaded Cauliflower Casserole
Low Carb Chicken Zucchini Casserole Recipe
Low Carb Chicken Zucchini Casserole Recipe with Gruyere Cheese Sauce
This low carb chicken zucchini casserole recipe comes with a delicious gruyere cheese sauce - and an EASY method to avoid a watery zucchini casserole!
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Tap on the times in the instructions below to start a kitchen timer while you cook.
Dissolve a tablespoon (14 g) of sea salt in a large bowl of warm water. Add the chicken and set aside to brine.
Meanwhile, heat a tablespoon of oil in a large saute pan over medium heat. Add the mushrooms and onions. Cook for about 7-10 minutes, until onions are translucent and starting to brown.
Increase heat to medium-high. Add the zucchini. Season everything with sea salt and black pepper. Stir fry for about 10 minutes, uncovered, until the zucchini is soft and a little browned. Most (if not all) of the liquid should evaporate.
Drain the veggies if any liquid remains and transfer to a large bowl. Set aside the bowl. Set aside the saute pan to use again.
Remove the chicken from the water and pat dry. Cut into bite-size pieces.
Add another tablespoon of oil to the saute pan and heat over medium-high heat. Add the chicken pieces and saute for 3-5 minutes, until browned on both sides and cooked through.
Add the chicken to the bowl with the veggies. Set aside the bowl. Set aside the saute pan to use again.
Preheat the oven to 400 degrees F (191 degrees C).
While the oven preheats, add cream and chicken broth to the same saute pan from before (it will just be at the bottom. Bring to a simmer, and simmer gently for about 5 minutes, until thick enough to barely coat the back of a spoon.
Reduce heat to low. Stir 2 oz (57 g) of shredded cheese into the pan, until melted. Add sea salt and black pepper to taste if needed.
Pour the sauce into the bowl with the chicken and veggies. Mix to combine.
Transfer the mixture to a 9x13 in (23x33 cm) glass casserole dish. Sprinkle with remaining shredded cheese.
Bake for about 10 minutes, until the cheese melts.
Last Step: Leave A Rating!
Serving size: ~4.5 x 3.25 in square, or 1/8 of entire recipe (cut casserole into 8 sections)
Nutrition facts are provided as a courtesy. Have questions about calculations or why you got a different result? Please see our nutrition policy.
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