Cheesy Baked Zucchini Casserole {Keto}
This creamy, cheesy Baked Zucchini Casserole is made with fresh zucchini, rich cream, and lots of cheese! It is an easy keto zucchini recipe that everyone will love.
This simple baked zucchini casserole recipe is a great recipe for using up all of that amazing summer zucchini. I love this recipe because it is made with just a few simple ingredients so the flavor of the fresh zucchini isn’t lost and it’s also keto!
That’s right, this Cheesy Zucchini Casserole is a gluten free, keto, side dish that everyone in my family loves. It’s fresh zucchini covered in a rich, creamy cheese sauce made with Gruyere cheese, and perfectly melted Parmesan cheese on top. What’s not to like?
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What You Will Need to Make Cheesy Baked Zucchini Casserole:
- Zucchini – Grow your own, pick it up at the local farmer’s market, or grab some at the grocery store. If you want a little variety, you can mix in some yellow squash too. For this recipe buy the thickest zucchini you can so you get nice, big, round slices to layer into your casserole.
- Onion – This adds a little more flavor to the dish, and onion goes so well with the slightly nutty flavor of the Gruyere cheese.
- Garlic – No recipe is complete without a little garlic. Mixed with the onions it adds just the right amount of flavor.
- Heavy Cream – This makes the cheese sauce thick, creamy, and totally amazing. You can find it in the diary section of the grocery near the milk. Sometimes it is referred to as heavy whipping cream.
- Cheese – For this recipe, you’ll use Gruyere cheese and Parmesan cheese. If you can’t find Gruyere, you can substitute Swiss cheese, and of course, you can always substitute low-fat or nonfat cheese if you prefer.
How to Make Cheesy Baked Zucchini Casserole:
- In a baking dish place the prepared zucchini slices in rows one on top of another until the dish is filled. Set dish aside.
- In a skillet over medium-high heat saute the diced onions with the butter, cooking them until they begin to soften.
- Add minced garlic and continue cooking for 2 minute to slightly soften it.
- Pour the heavy cream into the pan stirring until it begins to bubble.
- Add the Parmesan cheese and Gruyere cheese to the heavy cream, onions, and garlic. Stir together until the cheese melts.
- Pour the cheese sauce over the zucchini spreading it evenly over the zucchini.
- Cover the casserole dish with foil and place in the oven and bake at 450 degrees F for 15 minutes. Then remove the foil, top with the remaining Gruyere and Parmesan cheese and bake for 5 minutes more or until the cheese is melted and bubbling and the zucchini is tender.
- Remove from oven and serve.
How Thick Should the Zucchini Slices Be?
Since we want the zucchini to bake until all of that delicious cheese is melted you want to slice the zucchini into 1/4 inch thick pieces. Making the slices this thick means that the zucchini won’t turn into mush as it bakes. The thicker zucchini slices can withstand the longer cooking time and come out of the oven cooked through but still al dente.
How to Keep Your Zucchini Casserole from Being Watery
Zucchini has a lot of water in it. That means that when it bakes it can release a lot of excess water making your baked zucchini come out watery. So when you’re preparing the zucchini for your casserole you want to make sure to remove as much of that water from it as possible before baking.
It’s a simple process but it does take a little extra time. I promise you though, in the end it’s totally worth it.
After cutting your zucchini lightly salt it on both sides. Then play the slices on a thick layer of paper towels. Let the slices sit for 15 minutes, then flip them over and let them rest for another 15 minutes. You’ll see how much water comes out of the zucchini and is absorbed by the paper towel!
Looking for More Easy Zucchini Recipes?
- Refrigerator Zucchini Pickles
- Chicken Alfredo Zucchini Lasagna
- Zucchini Soup
- Crispy Fried Zucchini
- Zucchini Pad Thai
- One Pot Low Carb Shrimp Alfredo
- One Pot Summer Vegetable Pasta
- Ratatouille
- Spiralizer Recipes
- Summer Zucchini Recipes
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Cheesy Baked Zucchini Casserole
Ingredients
- 40 ounces (approximately) Zucchini, large, sliced 1/4 inch thick
- 1 teaspoon Salt
- 2 tablespoons Butter
- 5 ounces Onion, diced
- 2 cloves Garlic, minced
- ½ cup Heavy Cream
- 6 ounces Gruyere Cheese, grated and divided
- 4 ounces Parmesan Cheese, grated and divided
Instructions
- Preheat oven to 450 degrees F.
- Prepare zucchini by slicing it and then lightly salting it on both sides. Place the salted zucchini slices on a layer of paper towels and let sit for 15 minutes before flipping and letting sit for another 15 minutes. This will remove the excess water from the zucchini before baking.
- In a baking dish place the prepared zucchini slices in rows one on top of another until the dish is filled. Set dish aside.
- In a large skillet, melt butter over medium heat.
- Add onion to the skillet and cook for 2-3 minutes until it begins to soften. Then add garlic and cook for 2 minutes more.
- Pour the heavy cream into the pan stirring until it begins to bubble.
- Add 2 ounces of Parmesan cheese and 4 ounces of Gruyere cheese to the heavy cream, onions, and garlic. Stir together until the cheese melts.
- Pour the cheese sauce over the zucchini spreading it evenly over the zucchini.
- Cover the casserole dish with foil and place in the oven and bake at 450 degrees F for 15 minutes. Then remove the foil, top with the remaining Gruyere and Parmesan cheese and bake for 5 minutes more or until the cheese is melted and bubbling and the zucchini is tender.
- Remove from oven and serve.
From your pictures it shows not only zucchini squash but sliced yellow squash in the recipe. Why aren’t the yellow squash listed in the recipes or did we miss them? Thanks
Hi Lynsey, we did use a mix because we wound up needing more than we expected and squash is what we had on hand. Squash works just as well as zucchini so feel free to mix and match! 🙂
My creamy sauce was lumpy, any suggestions on it being smooth?
Did you stir it constantly when adding the heavy cream? It should not have any lumps, since the sauce is made of heavy cream and different types of cheese. Did the cheese melt completely?
The onions make it look lumpy? Maybe that’s it? Great recipe.
Yes they do and also make it taste delicious 🙂
Just served this-yummy
Used Swiss cheese instead of guyere. Served with grilled salmon & green salad
Made this tonight to serve with a chicken dish and it was absolutely stellar. I swapped the gruyere with gouda because we are gouda fanatics but this was one of the best zucchini dishes I have ever made. Great recipe!
Looks yummy! I’ll try this one! The only thing I could think of to add is …..bacon!
Mmm, now I need to make it again with bacon…
I love zucchini, especially when the farmers markets are in season. This looks like a fantastic summer treat!
This sounds and looks amazing. I don’t weigh my food. How many med sized zucchini is 40 oz? And what size dish will I be cooking this in? I need to double it but need more specific instructions. I am a beginner. 😊
You can use an 11×7 or 9×13 inch casserole dish. I used about 8 medium zucchini but since zucchini size can vary so much I suggest buying a little more than you think you need and continuing to slice zucchini until it fills your dish :).
Accidentally grabbed my bottle of minced ginger instead of minced garlic! I noticed it right after I squeezed 2 big glops into the sauce. WOOPS!! I added some garlic and crossed my fingers. It’s in the oven now. Praying that it turns out as tasty as it looks and smells.
Sometimes mistakes in the kitchen create wonderful recipes! How was it?
Sometimes zucchini can have a lot of liquid when cooked down. How do you keep this from coming out too runny?
Hi Sandi, we didn’t do it for this recipe, but you can reduce the amount of water released by slicing the zucchini and laying the slices on a paper towel, then sprinkle them with a little salt. Let the slices sit for at least 30 minutes and then use another paper towel to wipe up the water that has been released. This makes a big difference when cooking zucchini.
Just made this, and it is so delicious. I used mozzarella cheese in place of the gruyere.
So glad to hear! I will have to try mozzarella next time too.
This is an amazing dish. Served it on Easter and it was gone.. except for the little dish I saved for myself for breakfast the next day!
Adding the extra cheese and the end under high heat…..brilliant!
I LOVE LOVE LOVE all things zucchini. I made a double batch of this to go along with dinner tonight. Good thing because I have been ‘sampling’ it ever since it came out of the oven. This is SOOOOO GOOOOOOD!!! And so easy to make. It will definitely be going into my recipe rotation. I just won’t tell anyone there were two pans of zucchini = )
Making this tray. Cannot wait. Im using half and half as the store is out of whipping cream. Crossing my fingers.
Can you make this with some sort of substitute for the heavy cream?
You can try half and half or milk, but it may be watery.
I don’t know what I did wrong but the sauce just went to one great big lump
The only thing I can think is that maybe there was a little too much cheese? Or maybe the cream cooked down a little before the cheese was added so there wasn’t enough liquid?
I put the cheese on the best I could anyway and cooked it and it turned out great and was delicious wil try it again thank you
Great recipe but I think you meant to say slice zucchini into 1/2” slices, not 1/8”. That is half of a quarter inch. You can basically see through the slice it’s so thin!
Hi there, 1/8 inch is not a typo. That is how thin my mandolin slices the zucchini. It isn’t paper thin and it ensures that the zucchini cooks through in the time it is in the oven. If you cut the pieces into 1/2 inch slices you would need to increase the bake time.
Two questions:
Can you do the prep and then refrigerate it overnight before baking it?
Have you tried freezing left-overs? I am looking for something to heat up quick in the microwave when we get home.
Hi Diane, you should be able to prep the night before with no problem. Freeze any leftovers in an airtight container and microwave as usual.
Thank you Melinda. I did try this recipe and I loved it!!
Hi there! I saw you sort of answered this question in the comments below, but I want to be clear before I make this for thanksgiving 🙂 Question about prepping ahead. You said it should be fine but does that mean you can put the whole thing together the night before, put it in the fridge and just do the baking the next day? The cheese sauce won’t, like, coagulate or anything weird? Let me know as soon as you can, thanks!
I honestly can’t say as I’ve never made this casserole ahead of time. I can say that it reheats well so I believe the cheese sauce would be ok. My biggest concern would be that it would pool on the bottom and not coat the zucchini as well if it sat overnight before baking.
I’ve made this several times and it’s always turned out amazing! Do you think this would work in a crockpot? And if so, how could that be done?
Do you know if this would freeze well? I’d like to cut it in pieces and freeze individually.
Here is my hesitation with freezing it. I personally don’t like freezing zucchini and reheating it. I think it gets too soft and releases even more water. That’s just my opinion though! If you try it please let us know what you think.
in CHEESY BAKED ZUCCHINI CASSEROLE:
What can I add instead of Gruyere Cheese?
it looks delicious I want to try it!
Any swiss cheese is a good substitute for Gruyere. You could also use Parmesan cheese (fresh grated so it will melt), or a mix of Parmesan and mozzarella.
Quick question, why in a keto recipe would you suggest substituting low fat or non fat cheese?
Hi Cameron, some people enjoy this recipe who are not following a keto diet. Zucchini casserole is very popular in the summer! We added the note so that people who are interested in the recipe but are following a different diet know that it still works with different cheese.
We started harvesting the zucchini and this recipe is by far the best dish I have made. I made it with Gruyere cheese and served with baked parmesan crappie. My husband and I fought over it. We ate it all! It made two servings….lol
That sounds delicious! So glad you liked it!
Sooooo yummy! I almost ate the whole tray!
I had a liquidity issue but blame myself for ignoring your advice to dry out the veggies before cooking. Also, I baked this mid-quarantine, so I had to work with what I could find… mozzarella and pepper jack cheeses. SO GOOD! I’m almost afraid to cook it “correctly” because I just know how much of it I will eat 🤣🤤
Don’t know why my review dropped to 4 STAR but this recipe is definitely a 5 😋
Fun, easy and delicious🥰😋also bonus..not much clean up (hehehe) definitely a keeper 😉😋
I made this for supper and it was great. I didn’t get all the water out and it was a little runny, but the flavors were great so the extra liquid didn’t matter❤️
This is the best zucchini recipe I have ever eaten, instead of sharing my zucchini from my garden with my friends ,I now bake this recipe for them, They love to see me knocking on the door.
This is delicious! I used summer squash and zucchini, and I forgot to do the remove the water step but it still came out wonderful and I can’t wait to make it again
Has anyone made this ahead of time and put it in the freezer?
Could you make this with frozen zucchini slices? And if so, how would you go about soaking up as much water as possible?
I can’t eat squash. Could I substitute cauliflower steaks or turnip?
Yes you can.
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