Squash Casserole is literally summer on a plate.

This easy side dish has both zucchini and yellow summer squash topped with a crispy breadcrumb layer.

Quick to whip up and perfect for any meal, this dish will have everyone asking for seconds.

a spoon serving squash casserole

Ingredients in a Squash Casserole

While some recipes contain additives and fillers like eggs and bread crumbs, this squash casserole recipe focusses on the squash itself.

  • Onion: Onion adds flavor to this dish; stir in a little bit of garlic if you’d like.
  • Squash: Fresh yellow squash and zucchini are the stars here. Choose ones that are firm and bright in color for the best taste and texture.
  • Topping: butter, seasoned bread crumbs, and cheddar cheese add a perfect crisp topping to this recipe. Swap the bread crumbs for Panko breadcrumbs or crushed Ritz crackers or saltines to make a buttery cracker topping. Other cheeses such as Gruyere or Monterey jack can be used in this recipe.
  • Optional Add-Ins: red or green bell peppers, cheeses, garlic, tomatoes
slice yellow summer squash and zucchini on a wood cutting board

Make It Your Way

This yellow & zucchini squash casserole can be made to your preference as far as texture.

For a softer casserole, slice the zucchini a bit thinner, and when sauteeing in the frying pan, cook it a little bit longer so it’s tender-crisp but a bit on the softer side.

For tender-crisp squash, keep the zucchini at 1/4″ thickness. Be sure you don’t overcook it.

How to Make Squash Casserole

  1. Preparation: Slice up the onion and squash per the recipe below.
  2. Cook: Sauté the onion in butter and olive oil until tender, then add the squash and seasonings.
  3. Assemble: Place the cooked squash and onions into a greased casserole dish and top it with a mixture of breadcrumbs, melted butter, and cheese.
  4. Bake: Pop the casserole in the oven until the squash is tender and the topping is golden, usually around 35-40 minutes. Enjoy hot!
  • Place squash and onions upright (standing on the edge) in a casserole dish. Just tucke the onions into the squash mixture.

Topping Tip

Buttered bread crumbs cook quickly, so keep an eye on the casserole. If the crumbs are browned before the casserole is finished cooking, cover loosely with foil.

squash casserole in a white baking dish with bread crumbs

Can It Be Reheated?

Zucchini squash casserole tastes best when served fresh from the oven but of course it can be reheated.

Store leftover squash casserole tightly covered in the refrigerator for up to four days. The breadcrumbs won’t be as crisp but the squash itself will still taste delicious!

To reheat bake until hot (or you can reheat in the microwave). Then turn on the broiler element and put the heated casserole below the broiler for a few minutes of cooking to re-crisp the bread crumbs. Better yet, make a fresh batch of crumbs and top the leftovers with these.

Serving Suggestions

Zucchini squash casserole pairs well with just about any meaty main dish. Serve it with roasted or grilled chicken, barbecued ribs or hamburgers. It also goes great with Salisbury steak or pork chops with mushroom gravy.

Summer Veggie Sides

Easy Squash Casserole in a white dish with a serving spoon
4.97 from 60 votes↑ Click stars to rate now!
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Easy Squash Casserole

Slices of tender zucchini and yellow squash meld with a crunchy breadcrumb topping for a dish so satisfying and filling that you can even serve it as an entrée.
Prep Time 20 minutes
Cook Time 30 minutes
Servings 8


  • 1 small onion sliced
  • 1 tablespoon butter
  • 1 tablespoon olive oil
  • ½ teaspoon Italian seasoning
  • 2 pounds squash yellow squash and zucchini
  • salt & pepper to taste
  • ¼ cup grated parmesan cheese
  • ¼ cup cheddar cheese
  • cup seasoned bread crumbs
  • 2 tablespoons melted butter


  • Preheat the oven to 350°F.
  • Slice squash/zucchini into ¼-inch slices.
  • In a large skillet over medium heat, cook the onion in butter and oil until tender. Incrase the heat to medium-high and add the squash, Italian seasoning, salt, and pepper. Cook for 5 to 6 minutes or just until tender crisp.
  • In a greased 2 qt casserole dish, arrange the squash and onions so the squash is standing on its side.
  • Combine breadcrumbs, cheeses, and melted butter in a small dish. Sprinkle over squash.
  • Bake 35-40 minutes or until squash is tender.


If crumbs start to brown too much, loosely tent with foil.
    • For crisper squash cut it thicker, for softer squash, cut it thinner.
    • To keep the squash from releasing excess liquid, sauté in olive oil until slightly softened.
4.97 from 60 votes

Nutrition Information

Calories: 157 | Carbohydrates: 18g | Protein: 4g | Fat: 8g | Saturated Fat: 4g | Cholesterol: 18mg | Sodium: 179mg | Potassium: 431mg | Fiber: 3g | Sugar: 3g | Vitamin A: 12257IU | Vitamin C: 25mg | Calcium: 129mg | Iron: 1mg

Nutrition information provided is an estimate and will vary based on cooking methods and brands of ingredients used.

Course Main Course, Side Dish
Cuisine American

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taking a scoop of easy squash casserole from a white casserole dish


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About the author

Holly is a wine and cheese lover, recipe creator, shopping enthusiast and self appointed foodie. Her greatest passion is creating in the kitchen and making deliciously comforting recipes for the everyday home cook!
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Recipe Rating


  1. Love this squash recipe! It was delicious and nutritious, plus easy to fix! The breadcrumbs and cheese topping makes it a favorite and a keeper! 5 stars

  2. I followed the instructions to T, I had puddle of squash juice in bottom of my casserole dish. It tasted good with the additional Italian seasoning (I put about 1> Tablespoons in) and 3 or 4 minced cloves of garlic.3 stars

    1. Oh no! I haven’t had this issue so I can’t say for sure what happened James. Thank you for trying it.

  3. SO good! I make this casserole regularly. But take my advice; if you want to serve it with dinner, don’t bake it until the last minute. Mine usually doesn’t make it to the dinner table. As soon as it comes out of the oven, everyone wants a “just a bite” and it’s gone before dinner is ready. :0)5 stars

  4. Rather than cook the squashes in with the onions, I used the airfryer to desiccate them slightly for 7 minutes at 400 F.
    When they cooled I sprinkled with Italian seasoning, salt, pepper and garlic powder.
    After tiled in the casserole and sprinkling the crumble,, I cooked for 35 minutes at 350 F.
    Just delicious. I added some tomato slices to roast in the empty spot in the casserole.5 stars

  5. This was absolutely delicious. I used half the amount of Parmesan because it’s not one of my favorite cheeses but it was still the best casserole I ever had.5 stars

  6. Amazing! Even my husband who is not a fan of squash liked it! I made it according to the instructions. I also added a sprinkle of red pepper flakes. It was great. Just curious, how would it come out if you just layered the squash rather than stand it upright?

    1. So glad your family enjoyed it!

      I think it’d come out just fine layered. I stack them upright mainly because it looks nice but you also get a little bit more crispy bits on the edges of each piece.

  7. I have made this recipe 3 times for my family so far and each time the pan has been cleaned out. All say they love this recipe even the small kiddos.5 stars

    1. Definitely! You can swap equal amounts but you might like to add a bit of seasoning (salt/pepper).