Zucchini Squash Casserole Recipe

5 from 7 votes

Cheesy and comforting, this heart-warming easy Zucchini Casserole is a delicious side dish or vegetarian main dish that's easy to make.

Prep Time30

Cook Time45

Resting Time10

Total Time1 25

Course: Side Dish

Cuisine: American

Servings: Servings

Calories: 195kcal

Preheat the oven to 400º F and coat a 2 1/2 quart baking dish (8x10) or a 9x13-inch casserole dish with cooking spray.
Slice the zucchini into 1/4-inch thick rounds and place them into a colander or mesh sieve and set it over a large bowl. Sprinkle the zucchini with salt and toss it to coat it evenly (sprinkle additional salt if needed, it will help remove the excess water). Let it sit for 20 minutes to remove the additional moisture.
Melt the butter in a Dutch oven or a large pot over medium heat. Add the onion and season with the pepper and remaining salt. Sauté until the onions become fragrant, about 5 minutes. Add the minced garlic and continue to cook for 30 more seconds.
Once the zucchini has drained add it to the pot and cook, stirring occasionally until soft, about 5 to 7 minutes.
In a large mixing bowl whisk the heavy cream, eggs, cheddar cheese, and 1/4 cup of parmesan cheese together. Add the zucchini and onion mixture to the cheese filling and gently fold it together. Pour the entire mixture into the prepared baking dish.
In a small bowl combine the panko breadcrumbs, the remaining parmesan cheese, and the melted butter. Sprinkle on top of the casserole (I like to spread it unevenly so some of the zucchini is peeking through the top).
Place the casserole into the oven to bake for 30 to 35 minutes or until the top has turned a golden brown and the center is set. Let it rest for 10 minutes before serving.

Drain the zucchini. Zucchini has a high moisture point and therefore it's important to let the water drain by salting it and letting the zucchini sit. You'll end up with a mushy casserole if you skip this important step.
If the panko topping is browning too quickly while it bakes cover it with foil until it's finished baking.
Got leftovers? This makes a standard 9x13-sized casserole so if you find you have leftovers and want to change it up you can turn it into a main dish by adding some cooked meat like chicken or serve it over pasta such as egg noodles.
Change up the recipe. Make it into a tomato and zucchini casserole by adding in some seasonally fresh sliced tomatoes. Just make sure to salt and drain them along with the zucchini before adding them in.

Storage and Leftovers - This casserole will last for up to 4 days if stored in an air-tight container in the fridge. You can also make it up to 2 days in advance of when you plan on serving it.
Freezing Instructions - Prepare the casserole as directed, however, leave off the topping, and allow it to cool completely. Let the casserole thaw in the fridge overnight and then add the topping before placing it in the oven to heat.