I’ve shared plenty of zucchini recipes over the years, and the biggest mistake people make is treating zucchini like it doesn’t have a ton of water hiding inside. That’s how you end up with a soupy casserole instead of a rich, cheesy zucchini au gratin. This recipe is all about getting the texture right, tender zucchini covered in a creamy sauce with plenty of melted cheese, without a puddle of liquid sitting at the bottom of the dish.
This Easy Zucchini Au Gratin is a healthy baked casserole loaded with cheese! This gooey side dish is layered with cheddar, mozzarella, and Parmesan cheese for the perfect dose of flavor. Who says veggies can't be fun?
Have you had my Instant Pot Scalloped Potatoes Au Gratin? Did you wish there was a version with fewer carbs? Well, this is it.
Zucchini Au Gratin Ingredients
- Zucchini
- Butter
- Garlic
- Heavy Whipping Cream
- Cream Cheese
- Cheddar Cheese
- Parmesan Cheese
- Mozzarella Cheese
- Onion Powder, Salt, and Pepper
How to Make Zucchini Gratin
Detailed measurements and full instructions can be found in the recipe card at the bottom of this post.
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- Preheat oven to 400 degrees.
- Place the sliced zucchini on a flat surface with towels or paper towels. Sprinkle both sides of the zucchini with salt.
- Allow the zucchini to sit for 30 minutes.
- Heat a saucepan on medium-high heat and add butter.
- When melted, add garlic.
- Add in cream cheese, whipping cream, Parmesan reggiano, and shredded cheddar cheese. Add in onion powder, salt, and pepper to taste.
- Spray a 9x13 baking dish with cooking spray. Arrange the zucchini in rows throughout the dish. Drizzle the cheese sauce throughout.
- Sprinkle shredded cheddar and the mozzarella throughout the pan.
- Bake.
Zucchini Au Gratin Recipe
Ingredients
- 3-4 whole fresh zucchini Sliced ¼-1/2 inch thick into slices. Unsliced, mine weighed 3 pounds.
- 1 tablespoon butter
- 2 garlic cloves minced
- ¼ cup heavy whipping cream
- 4 oz cream cheese
- 1 cup shredded cheddar cheese Divided into 2 servings.
- ¼ cup shredded parmesan reggiano cheese
- 1 teaspoon onion powder
- salt and pepper to taste
- ½ cup shredded mozzarella cheese
Instructions
- Preheat oven to 400 degrees.
- Place the sliced zucchini on a flat surface with towels or paper towels. Sprinkle both sides of the zucchini with salt.
- Allow the zucchini to sit for 30 minutes. This will sweat out the excess moisture of the zucchini. Skipping this step will result in a watery dish. After the 30 minutes. Blot and wring out any excess moisture.
- While the zucchini rests, prepare the filling for the dish. Heat a saucepan on medium heat and add the butter.
- When melted, add the garlic and cook for a couple of minutes until fragrant.
- Add in the cream cheese, whipping cream, Parmesan reggiano, and ½ cup shredded cheddar cheese. Stir. Add in the onion powder, salt, and pepper to taste. Taste the sauce repeatedly and adjust the flavor to taste as needed.
- Stir continuously until the cheese has melted.
- Remove from the heat and set aside.
- Arrange the zucchini in rows throughout a 9x13 baking dish. Drizzle the cheese sauce throughout.
- Sprinkle the remaining ½ cup of shredded cheddar and the mozzarella throughout the pan.
- Bake (uncovered) for 30-35 minutes until golden brown. If you like a crisp top, a couple of minutes before the dish has finished baking, turn on the Broil function on the oven. Broil for 1-3 minutes until the top has crisped.
- Cool before serving.
Video
Notes
- If you allowed the zucchini to rest and your dish is still too watery, saute or grill the zucchini beforehand. It will add flavor and dry out the zucchini.
- You can add Italian Seasoning (about 1 teaspoon) if you are looking for zest, or serving this with an Italian themed main dish.
- You can use any cheese you wish. It's up to you. I purchase block cheese and grate it myself. Pre-shredded cheese typically has preservatives and corn starch. It does not melt as well. Keep this in mind if you choose not to make the dish using my method.
- You can make this using shredded zucchini or zucchini noodles if you wish.
- You can reduce the amount of fat in the recipe by using low-fat cream cheese and cheese in the recipe. You can also lessen the amount of cheese used.
- This is not a dish I would prep and make ahead because it will alter the texture of the cheese and it will harden.
Nutrition (displayed with net carbs)
Frequently Asked Questions and Recipe Pro Tips
You usually hear these terms when referring to potatoes. Both of these are considered casserole like dishes and both are served with a creamy sauce. Scalloped potatoes do not use grated cheese, they are usually made with just heavy cream and milk.
A lot of au gratin recipes will use breadcrumbs for an even crisper topping! I love that method as well, but you can accomplish a similar result by broiling the dish to toast the cheese a little bit right before you pull it out of the oven.
You can read more about The Difference Between Scalloped and Au Gratin here.
Zucchini is a very watery vegetable. Zucchini is 94% water. If you slice up the zucchini and add it to the dish without preparing it properly beforehand, you will end up with something that looks a lot like soup.
After you have sliced the zucchini arrange it on a flat surface with towels or paper towels. Sprinkle salt throughout and let it sit for at least 30 minutes. You will see moisture and water appear. Blot the excess and wring out any water you can.
Try to remove as much as you can. Since the veggie is mostly water, getting it all out isn't really possible, but it will help a ton. Another tip you can do, if your dish is too watery, is saute or grill the zucchini beforehand. It will add flavor and dry out the zucchini.
My preference is to slice it into ¼ inch rounds using this mandolin from Amazon. ½ an inch thick will work as well.
I like to use a combination of cheddar, Parmesan Reggiano and mozzarella. You can use any cheese you wish. It's up to you. I purchase block cheese and grate it myself. Pre-shredded cheese typically has preservatives and corn starch. It does not melt as well. Keep this in mind if you choose not to make the dish using my method.
No. The skin is tender, completely edible, and helps the zucchini slices hold their shape. It also adds a little color to the finished dish.
Aim for even slices so everything cooks at the same rate. A mandoline works great for this, but a sharp knife will do the job, too.
I bake the dish uncovered for 30-35 minutes. If you like a crisp top, a couple of minutes before the dish has finished baking, turn on the Broil function on the oven. Broil for 1-3 minutes until the top has crisped.
You can prep some of the components ahead of time, but I prefer baking it close to serving. Once zucchini is combined with salt and sauce, it starts releasing moisture, so assembling it too far in advance can make the dish watery.
The zucchini should be tender when pierced with a fork, the sauce should be hot and bubbling, and the cheese on top should be melted and golden.
You can store the dish tightly sealed and covered for 3-4 days.
You can freeze this dish, but note that when reheated, dairy separates. This does not typically impact the flavor, but it will impact the look.
Pair this with these Main Dishes
Keto Low Carb Smothered Pork Chops
Smothered Chicken Thighs
Air Fryer Cornish Hens
Air Fryer Whole Chicken
Air Fryer Steak
More Zucchini and Side Dish Recipes
Keto Low Carb Zucchini Shrimp Alfredo
Keto Low Carb Zucchini Bread
Air Fryer Zucchini Chips
Zucchini Lasagna Roll Ups
Zucchini Taco Boats
Zucchini Pasta Salad
Roasted Brussel Sprouts with Garlic
Broccoli Au Gratin
Southern Green Bean Casserole
Rachael says
Oh. My. Lanta. I'm not sharing with my family. I'm gonna eat the whole pan by myself. Where had this recipe been all my life???
staysnatched says
haha! This is so relatable.
Lacey says
Can you prep the zucchini a day ahead of time? The salting and paper towel part? Refrigerate and then paper towel them again the next day after it goes room temperature?
staysnatched says
I've never tried it, but probably!
Mary says
This was just ok. Not that much flavor.
staysnatched says
You should always season to taste for flavor.
Lisa says
This is delicious! I used two zucchini, two yellow squash on 1/2 the pan. Then, sliced Yukon gold potatoes with a little sliced onion on the other half. Spread that yummy cheese sauce all over! Wonderful!
staysnatched says
Yay! I'm so glad you enjoyed it!
Pam Reynolds says
Everyone loves eating their veggies this way, tons of compliments! I double the sauce and put less cheese on top. The sweating of the zucchini is a pain but needs to be done. I've had soggy zucchini too many times.
Brandi Crawford says
Yes! So true. It has to be done.
Debbie says
We really liked this. I didn't have whipping cream so I substitued regular milk with a tiny bit of flour as a thickener. It worked out well.
Brandi Crawford says
I'm glad you liked it!