Healthy Zucchini & Squash Casserole Recipe

Healthy, simple, and fabulous, this Zucchini and Squash Casserole is the best low-carb recipe for Summer squash! Yellow squash and zucchini are baked in the oven to perfection with a crispy crust made from Parmesan cheese and breadcrumbs. This easy casserole is amazing for Summer picnics and potlucks, and makes the perfect side dish for any holiday dinner!

Zucchini and Squash Casserole Recipe

Zucchini and yellow squash are some of the overlooked vegetables that somehow magically reappear during the summer months and at a Thanksgiving table.

I first discovered my love of cooking with this delightful combo when Cohl started coming home with enormous bags full of fresh summer produce from a fellow dentist at his office.

After making a few batches of this Sauteed Zucchini and Squash, I started to run out of new recipe ideas.

And then one week he came home and the bag was packed to the brim with yellow summer squash and zucchini.

It would be a sin to let them all go bad, so I had to brainstorm a new summer recipe.

Squash casserole has always been one of my favorite summertime side dishes.

But this time it would be a healthier version that was still simple to make and baked in the oven.

Ingredients

Sure, the cheesy and cream-laden squash casseroles taste ah-maaazing, but let’s be real… all of that dairy takes away the incredible flavor of the fresh vegetables!

The ingredients for this zucchini and yellow squash casserole recipe are pretty simple.  You probably have most of them in your kitchen already:

• Squash – Feel free to use all yellow squash or all zucchini if that’s what you have. However, the alternating colors are what make this casserole so unique and pretty!
• Olive oil – You can also use any other type of healthy oil that does not have a ton of flavor. Avocado oil, safflower, and sunflower oil will all work equally as well.
• Garlic Powder – The secret ingredient that gives this dish a unique flavor!
• Parmesan cheese – Regular, dairy-filled, Parmesan cheese is best. You can also use a vegan and dairy-free Parmesan cheese.
• Panko Breadcrumbs – You can use regular breadcrumbs or gluten-free breadcrumbs. The taste will be minimally affected.
• Parsley – Not absolutely necessary but makes the casserole really pretty when serving.

Expert Tip: You can substitute with a seasoned breadcrumb mixture, but you will need to make sure to adjust the amount of salt you add!

Preparing Squash for Casserole

To get the Summer squash ready to bake there are a few things to do.

First, you need to slice it into uniform pieces. You can either use a mandoline (if so be very careful with fingers!), or you can thinly slice them by hand.

You want them to be ¼-inch thick. If they end up thicker, it will need to cook longer. If thinner, it will likely be soggy instead of crisp.

Next, sprinkle salt over all of the sliced squash and let sit for 10 minutes. Then wipe away any excess moisture that forms with a paper towel.

This little trick allows the sliced zucchini and squash to release a large amount of the water they retain. It will help you to get a crispy, and not soggy, casserole.

How to Make

As I mentioned previously, this recipe is not only healthy, but it is also extremely easy to make. Here are the steps for how to make a zucchini and squash casserole:

Meal Prep and Storage

You totally can prep-ahead and have this side dish ready-to-go when you are.  This is especially handy when it comes to preparing a healthy casserole for a backyard BBQ, picnic, or Thanksgiving day.

• To Prep-Ahead: Follow all directions but wait to bake until you’re ready to serve. Cover tightly with foil and refrigerate for up to 2 days. Bring to room temperature and bake according to directions.
• To Store: If there happen to be leftovers, store in an airtight container in the refrigerator.
• To Reheat: Preheat your oven to 300°. In an oven-proof dish bake the zucchini and squash for 10-12 minutes or until heated through. You can also broil the casserole again for 1-2 minutes to bring back some of that crunchy topping.

FAQs

Expert Tips and Tricks

• Use a mandoline. This gives you the most precise slices so they all cook at a similar rate.
• Sprinkle a little salt to prevent a soggy mess. Let the salted squash sit, then blot dry. The salt releases excess moisture.
• Try out Italian breadcrumbs. Since they’re pre-seasoned and often contain salt, you will have to adjust the other seasoning ingredients.
• Broil it at the end. This gives it a great crunchy topping.
• Use all of one squash – If it’s all you have, either use all zucchini or all yellow squash.

Other Squash Recipes

If you like this Summer squash casserole, make sure to check out these other recipes:

Baked Parmesan Zucchini Fries

Crispy Zucchini Fritters

How to Make Zucchini Noodles

Zucchini Lasagna Roll-Ups

Sautéed Zucchini and Squash

More healthy side dish recipes.