Easy Zucchini Au Gratin

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? 

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Have you had my Instant Pot Scalloped Potatoes Au Gratin? Did you wish there was a version with fewer carbs? Well, this is it.

The Difference Between Scalloped and Au Gratin

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.

How to Slice the Zucchini

My preference is to slice it into 1/4 inch rounds using this mandolin from Amazon. 1/2 an inch thick will work as well.

How to Prevent Excess Water From the Zucchini

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.

How to Make Zucchini Gratin

1. Preheat oven to 400 degrees.
2. Place the sliced zucchini on a flat surface with towels or paper towels. Sprinkle both sides of the zucchini with salt.
3. Allow the zucchini to sit for 30 minutes.
4. Heat a saucepan on medium-high heat and add butter.
5. When melted, add garlic.
6. Add in cream cheese, whipping cream, Parmesan reggiano, and shredded cheddar cheese. Add in onion powder, salt, and pepper to taste.
7. Spray a 9×13 baking dish with cooking spray. Arrange the zucchini in rows throughout the dish. Drizzle the cheese sauce throughout.
8. Sprinkle shredded cheddar and the mozzarella throughout the pan.
9. Bake.

How Long to Cook and Bake

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.

What Type of Cheese to Use

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.

How to Store It and How Long It Will Last in the Fridge

You can store the dish tightly sealed and covered for 3-4 days.

Freezer Tips

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
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