This healthy yellow Summer Squash Casserole is an easy and delicious way to use up fresh yellow squash this summer! This side dish has tender sliced squash, gooey melted cheese, fresh basil, and golden breadcrumbs making it a great bet for picnics, potlucks, or any summer dinner. Plus, you can make it ahead of time and just pop it in the oven!

summer squash casserole with bread crumbs

Why We Love This Recipe for Healthy Summer Squash Casserole

My kitchen is overflowing with vegetables in the summer, and recently I’ve had an abundance of yellow summer squash! It’s such a delicious and nutritious vegetable, so I’m not complaining, but it means I have to get crafty to make sure it doesn’t go to waste. 

Thankfully, I’ve been down this path before with zucchini, and I wound up making Healthy Zucchini Casserole which was a raging success in my household. This time around I subbed the zucchini for some classic summer squash and added breadcrumbs, basil and cheese to create the most perfectly gooey summer casserole. Plus, it’s healthy!

You can enjoy this casserole as a side dish for a weeknight meal or as the winner in the “who brought the best potluck dish to the cookout” contest (even if it’s only awarded in your mind – it still counts). We love pairing this healthy squash casserole with everything from Cajun Flank Steak, Barbecue Chicken, to the classic Garlic Lemon Chicken

Whatever you serve it with, your summer squash casserole will hold its own. Between the gooey cheese and tender squash, there’s no way this dish will go unnoticed!

Key Ingredients for this Recipe

ingredients for summer squash casserole with breadcrumbs and cheese

Yellow Summer Squash

You’ll need six whole summer squash for this recipe! That said, since size varies for garden-picked yellow squash, you’ll want to aim for about 3 pounds, cut into rounds. Summer squash is nutrient-packed and the perfect flavor to be the base for this summer casserole.

Sourdough Bread

Many squash casserole recipes will include Ritz crackers or cracker crumbs and butter for the topping. We have instead opted for a healthier, yet still delicious breadcrumb topping made with sourdough bread.

Two slices of sourdough bread should be enough. You’re going to blitz them in a food processor to make a coarse breadcrumb consistency. The dry sourdough will soak up all the moisture, spices, and cheese to form a gooey filling.

The breadcrumbs helps the squash hold together so you do not need to add any additional eggs or fillers to make the casserole.

Cheese

Due to the high water content in summer squash, we didn’t need to add any more liquid in the form of a cheesy cream sauce. Nor did we want to add in heavy cream. Instead we opted for a combination of some of our favorite cheeses! They add richness and flavor, but don’t add any additional moisture.

Both Italian blend cheese and parmesan cheese play a role in this dish. For the Italian cheese, you’re going to want to look for Italian Blend or Pizza Blend in the grocery store.

Step By Step Instructions For Making This Squash Casserole

making breadcrumb mixture and mixing it with summer squash and cheese

Step 1: Blend Breadcrumbs

Preheat your oven to 375 degrees F. Meanwhile, fit your food processor with the steel blade attachment and drop the garlic through the feed tube to mince with the motor on. Tear the sourdough bread into three or four pieces each and add them to the food processor. Cover and process until the bread forms coarse crumbs. With the motor running, drizzle in olive oil.

This mixture will be tossed with the squash to help soak up some of that excess liquid that cooks out of it, and it will also become the golden crunchy topping!

Step 2: Combine Ingredients

Toss ¾ cup (about half) of the breadcrumb mixture, squash, tomato, basil, salt, and pepper in a large bowl to combine.

summer squash casserole topped with breadcrumbs and cheese

Step 3: Assemble Casserole and Bake

Coat a 9 by 13 inch (or similar volume) casserole dish with cooking spray. Spread half of the squash mixture in the casserole dish and top the mixture with half of the Italian cheese blend. Add the remaining squash.

Do not top with cheese yet, instead cover the casserole with foil. Bake until the squash is fork-tender, which is about 50 to 55 minutes.

Step 4: Add Topping and Bake Until Done

After about 50 minutes, increase oven temperature to 450 degrees F. Remove the foil, and top the casserole with the remaining Italian cheese blend, Parmesan, and the remaining breadcrumbs. Bake the casserole uncovered until the cheese is melted and the topping is golden brown, which should be about 12 to 15 minutes. 

summer squash in a white baking dish topped with crunchy breadcrumbs

FAQs and Expert Tips

How do you keep squash casserole from getting watery?

The breadcrumbs in this dish wind up absorbing the moisture and melding into a cheesy, gooey, filling so there’s no watery aspect to this dish.

Can I freeze this casserole or make it ahead?

I wouldn’t recommend freezing it since squash holds so much moisture. You can make it about 8 hours ahead of time and keep it refrigerated though. Cover the uncooked casserole with plastic wrap and be sure to store the reserved breadcrumb mixture separately in an airtight container.

Is crookneck squash the same as yellow squash?

It’s a type of yellow squash! There’s both straight neck and crookneck yellow squash and you can use either for this recipe.

Variations To Try

  • Add bell peppers: Dice and sauté the one bell pepper in a large skillet over medium heat until they are tender. Let the pepper cool slightly before stirring them into the squash and breadcrumb mixture with the tomatoes.
  • Use Butter Instead of Oil: For a richer buttery taste, use melted butter instead of olive oil
  • Cheddar Cheese: Use shredded extra sharp cheddar cheese instead of the Italian cheese blend.
  • Use Half Zucchini: Substitute half of the yellow squash with zucchini for a multi colored effect. You can also make this casserole with a blend of summer squashes such as patty pans and yellow zucchini if you’d rather not stick to one.
  • Add Fresh Corn: Cut the kernels from two ears of sweet corn and add to the bowl with the quash and breadcrumb mixture.
  • Vidalia Onion: Many classic southern side dish versions of summer squash casserole include sautéed vidalia onion. To add one to this recipe, finely slice it, and then sauté in one tablespoon of butter over medium-low heat until softened, about 8 minutes. Add to the top of the casserole before covering with foil and baking.

Additional Recipes to Try

summer squash casserole with a scoop missing and sprinkled with browned breadcrumbs and herbs

Thanks so much for reading. If you are new here, you may want to sign up for my free weekly email newsletter where I share weeknight meal plans delivered right to your inbox. Or follow me on Instagram. If you make this recipe, please come back and leave a star rating and review! It is very appreciated. Happy Cooking! ~Katie

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summer squash casserole with breadcrumbs, italian cheese, and parmesan

Healthy Yellow Summer Squash Casserole


  • Author: Katie Webster
  • Total Time: 1 hour 20 mins
  • Yield: 6 servings, about 1/4 cup each 1x
  • Diet: Vegetarian

Description

This healthy yellow Summer Squash Casserole is an easy and delicious way to use up fresh yellow squash this summer! This side dish has tender sliced squash, gooey melted cheese, fresh basil, and golden breadcrumbs making it a great bet for picnics, potlucks, or any summer dinner. Plus, you can make it ahead of time and just pop it in the oven!


Ingredients

Scale

1 clove garlic, peeled

2 slices sourdough bread, about 3 to 4 ounces

2 tablespoons extra-virgin olive oil

6 medium summer squash (about 3 pounds), cut into rounds

1 small ripe tomato, diced

2 tablespoons chopped fresh basil, plus more for garnish

1 ½ teaspoons coarse kosher salt (or to taste)

Freshly ground pepper to taste

4 ounces shredded Italian blend cheese (1 cup)

½ cup shredded Parmesan cheese


Instructions

  1. Preheat oven to 375 degrees F. Meanwhile, fit food processor with the steel blade attachment. Turn on motor and drop garlic through feed tube to mince. Remove lid and tear bread into three or four pieces each and add to the bowl of the food processor. Cover and process until the bread forms coarse crumbs. With the motor running, drizzle in olive oil.
  2. Toss ¾ cup (about half) of the breadcrumbs, squash, tomato, basil, salt and pepper in a large bowl to combine.
  3. Coat a 9 by 13 inch (or similar volume) casserole dish with cooking spray. Spread half of the squash mixture in the casserole dish. Top with half of the Italian cheese blend. Add the remaining squash and cover the casserole with foil. Bake until the squash is fork tender, about 50 to 55 minutes.
  4. Increase oven temperature to 450 degrees F. Remove foil, top with the remaining Italian cheese blend, Parmesan and the remaining breadcrumbs. Bake uncovered until the cheese is melted and the topping is golden brown, 12 to 15 minutes.

Notes

Ingredient Note:

This casserole can be made with any summer squash including zucchini, yellow crookneck or patty pan. Or you can use a blend of more than one! Remove the stem and blossom ends and slice into ¼-inch thick rounds.

Italian Blend Cheese: Look for Italian blend or Pizza blend.

Make-Ahead:

This can be prepared as directed through assembling and covering with foil in step 4. Do not bake. Refrigerate up to 8 hours ahead. Refrigerate the reserved breadcrumbs separately. 

  • Prep Time: 15 mins
  • Active Time: 20 mins
  • Cook Time: 1 hour 5 mins
  • Category: Side Dishes
  • Method: Oven
  • Cuisine: American

Nutrition

  • Calories: 212
  • Sugar: 5 g
  • Fat: 12 g
  • Carbohydrates: 17 g
  • Fiber: 5 g
  • Protein: 9 g

Keywords: Healthy Squash Casserole, Summer squash casserole,yellow squash casserole,