The squash casserole my mom’s farm inspired

London Lea, Justin Lea, and their son on her mom's family farm getting zucchini and squash.

If you’ve got summer squash multiplying faster than you can cook it, I know the feeling. My mom has a farm, and every summer she sends me home with bags and BAGS of zucchini and yellow squash.

I’ve turned that haul into just about everything, from Sautéed Zucchini and Squash and Parmesan Crusted Zucchini to a big batch of Crispy Zucchini Fritters. But there’s only so much a family can get through before some of it starts to go.

This Summer Squash Casserole was always one of my favorite summer sides growing up. The classic version is usually loaded with sour cream, mayo, and crushed Ritz crackers.

(Now don’t get me wrong… I LOVE those buttery crackers. Just not on a random Tuesday.)

So I made a lighter one. Just sliced zucchini and yellow squash layered up, salted so they don’t turn watery, and topped with Parmesan and crispy panko breadcrumbs.

A few minutes under the broiler and the top goes golden and crisp. It holds its own next to the heavy version, and it’s the one my family actually asks for again and again!

Ingredients and Substitutions

For the exact measurements and detailed instructions, please see the recipe card below.

Zucchini, yellow squash, salt, pepper, onion, oil, and garlic ingredients for a squash casserole side dish recipe.
  • Parsley. Not absolutely necessary but it makes the casserole really pretty when serving. You can also use fresh thyme or other herbs you love.
  • Squash. Feel free to use all yellow summer 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 oil that does not have a ton of flavor. Avocado, safflower, and sunflower oils will all work equally as well.
  • Garlic Powder. You only need a little bit, but it’s the secret ingredient that gives this dish a unique flavor!
  • Parmesan cheese. Regular, dairy-filled Parmesan cheese is best. You can also use vegan and dairy-free Parmesan cheese. If necessary, you can sub in another variety, like sharp cheddar cheese, but the result won’t be quite the same.
  • Panko Breadcrumbs. You can use regular breadcrumbs or gluten-free breadcrumbs. The taste will be minimally affected. You can substitute with a seasoned breadcrumb mixture, but you will need to make sure to adjust the amount of salt you add

Step-by-step Instructions

Please see the recipe card below for the full instructions, ingredient amounts, and a printable recipe.

Prep the squash.

Slice the squash into ¼-inch rounds using a mandolin or sharp knife. Thicker slices will need more time; thinner ones can turn soggy.

Sprinkle with salt and let sit for 10 minutes, then pat dry. This draws out excess moisture so the casserole bakes up crisp instead of watery.

Layer in the pan.

Layer the zucchini and yellow squash, alternating types, in a 9-inch square baking dish.

Season the casserole.

Lightly season the layered squash with salt and pepper.

Whisk together breadcrumbs, Parmesan cheese, and garlic powder. Then, pour the mixture in an even layer over the zucchini and squash.

Seasonings and cheese are sprinkled on top of the sliced squash.

Bake in the oven.

Cover the baking dish with aluminum foil and bake in preheated 350°F oven for 30 minutes. It may take a few minutes more if the slices were cut thick, or less time if the squash slices are thin.

Broil for 3-5 minutes. Keep a close eye on it!  The topping will crisp up and turn golden brown quickly.  

Healthy Summer Squash Casserole with Zucchini and Yellow Squash | Use up all of your summer squash in this super easy and healthy summer squash casserole. Made with yellow squash and zucchini squash, this recipe is a quick side dish for any meal.

Ways to change it up

  • Italian breadcrumbs: These work too. Just go easy on the added salt, since they’re already seasoned.
  • All one squash: Use all zucchini or all yellow squash if that’s what you’ve got. The alternating colors just make it prettier.
  • Cheese: Parmesan keeps it light and salty. A little sharp cheddar on top makes it richer if that’s the mood.
  • Herbs: Fresh parsley is my go-to, but thyme or basil are both great here.
  • Gluten-free: Swap in Aleia’s gluten-free panko and nobody will know the difference.

What makes this summer squash casserole lighter?

Most squash casseroles lean on sour cream, mayo, eggs, and a can of cream-of-something soup, then get topped with buttery Ritz crackers. This one skips all of it.

Instead, the squash gets layered up and topped with just Parmesan and crispy panko. No crackers needed, and it still bakes up golden and crisp on top.

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How to store and reheat squash casserole

  • Fridge: Let it cool, then store leftovers in an airtight container for 3 to 4 days.
  • Reheating: Pop it back in a 350-degree oven or the air fryer for a few minutes to bring back the crispy top. The microwave works in a hurry, but the topping goes soft.
  • Make ahead: Assemble the whole thing, cover, and keep it in the fridge for up to 2 days. Bring it to room temperature and bake right before serving.
  • Freezing: I don’t recommend freezing this one. Summer squash holds a lot of water, so it turns soft and watery after it thaws.

FAQs

How do you keep squash casserole from getting watery?

The answer to keeping your casserole from getting watery is to salt before cooking. Squash releases extra moisture while cooking. However, there is a trick to prevent this. After you’ve sliced your squash, sprinkle it with salt, let it sit for about 10 minutes, then blot dry the moisture that the salt drew out. 

Do you need to peel the squash?

Nope, leave the skin on. It’s thin and tender, it adds color, and it helps the slices hold their shape as they bake.

Can I use all zucchini or all yellow squash?

Totally. Use whatever you have, or whatever your garden is overrun with. The mix of colors just makes it prettier on the table.

Can I make this gluten-free?

Yes. Just use gluten-free panko breadcrumbs in place of regular. Everything else in the recipe is already gluten-free.

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4.94 from 89 votes

Zucchini and Squash Casserole Recipe

If you’re swimming in zucchini and squash, this Summer Squash Casserole is one of the most deliciously easy ways to use it up. It’s a lighter take on the classic (no mayo, sour cream, or Ritz crackers here!) that bakes up in the oven with a crispy Parmesan-panko topping for laid-back weeknights, potlucks, or holiday tables alike!
A hand picking up a serving of a healthy squash casserole recipe from a white porcelain baking dish and a blue towel underneath it.
Yield 6 servings
Prep 15 minutes
Cook 35 minutes
Total 50 minutes
An image of an envelope sealed shut with the Evolving Table logo.

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Ingredients 

  • 2 pounds summer squash zucchini and yellow squash, cut into ¼-inch slices
  • 2 ½ tablespoons olive oil
  • 1 ¼ teaspoons salt divided
  • ½ teaspoon pepper
  • cup grated Parmesan cheese grated
  • cup Panko breadcrumbs gluten-free
  • ¼ teaspoon garlic powder
  • 2 tablespoons fresh parsley finely chopped

Instructions 

  • Preheat the oven to 350℉.
  • Cut yellow squash and zucchini into thin, ¼-inch slices. Sprinkle ½ teaspoon salt over the zucchini and squash slices. Let sit for 10 minutes and then dab to remove excess moisture with a paper towel.
    2 pounds summer squash
  • Spray a 9-inch square baking dish with non-stick cooking spray. Alternatively, overlap the zucchini and squash in a row. You should be able to form 4 rows.* Drizzle olive oil over the zucchini and squash and then sprinkle with salt and pepper.
  • In a small bowl combine Parmesan cheese, breadcrumbs, and garlic powder. Toss to combine and then sprinkle over the zucchini and squash.
    ⅓ cup grated Parmesan cheese, ⅓ cup Panko breadcrumbs, ¼ teaspoon garlic powder
  • Cover baking dish with aluminum foil and bake in preheated oven for 30 minutes.
  • Remove foil and turn heat to a High broil. Broil for an additional 5-7 minutes, or until breadcrumb topping starts to turn a golden brown. Serve immediately with fresh parsley and enjoy!
Last step! If you make this, please leave a review letting us know how it was!

Tap stars to rate!

4.94 from 89 votes

Video

Notes

  • Cheese: Can use a vegan Parmesan cheese substitute.
  • Squash: I like to get small-medium, similarly-sized summer squash so they will be able to fit into four rows easily!
  • Tools: A mandolin gives you the most precise slices so they all cook at a similar rate.
  • Salt: A little salt will help prevent a soggy mess. Let the salted squash sit, then blot dry. The salt draws out excess moisture.
  • Breadcrumbs: Try out Italian breadcrumbs. Since they’re pre-seasoned and often contain salt, you will have to adjust the other seasoning ingredients.
  • Broiling: This gives it a great crunchy topping.
  • Storage: Store leftovers in an airtight container in the fridge for 3 to 4 days.
  • Make ahead: Assemble, cover, and refrigerate for up to 2 days. Bring to room temperature and bake right before serving.
  • Freezing: Not recommended. Summer squash holds a lot of water, so it turns soft and watery after thawing.

Nutrition

Calories: 114kcal, Carbohydrates: 8g, Protein: 4g, Fat: 8g, Saturated Fat: 2g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 5g, Cholesterol: 5mg, Sodium: 610mg, Potassium: 424mg, Fiber: 2g, Sugar: 4g, Vitamin A: 464IU, Vitamin C: 27mg, Calcium: 81mg, Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Made this recipe?Leave a comment below!

What to Serve with Squash Casserole?

This dish is an excellent side for family meals. Try one of these recipes alongside it.

For some flavor, try out this Hot Honey Chicken. Or get fancy with Chicken Cordon Bleu.

Skip the potatoes and try this zucchini casserole with Air Fryer Steak or Filet Mignon.

If you’re a seafood lover, go for Panko Crusted SalmonLemon Garlic Baked Salmon or Air Fryer Salmon.

Other Squash Recipes

If you love the simplicity of this summer squash casserole, make sure to check out these other easy squash recipes that are perfect for using up this summer produce.

4.94 from 89 votes (47 ratings without comment)

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Comments

  1. Hi,
    My neighbor has a vegetable garden and every summer he shares some of his harvest with my wife and me. Yesterday, he handed me 1 enormous zucchini and 1 equally huge summer squash. These things must be at least 3 lbs. each and measure 3 to 4 inches in diameter by 10 inches long. I am assuming that I should cut it all up and prepare at once and store the left overs in a container refrigerated. What do you recommend?

    1. Wow – those are huge squash! Yes, you can either cook them and then store in the refrigerator if you think you’ll eat them throughout the week. You can also Freeze Zucchini if you want to store some to use year-round! I’ve also just published a recipe for Zucchini Soup that you can use squash in there, too, to use up a bunch of it! Thanks for your question, Vaughn!

  2. 5 stars
    I made this recipe tonight and it is excellent! I did make some modifications. I only used 1 TBL of olive oil as I use very little oil in our cooking. I didn’t have Parmesan cheese. I used a vegan shredded mozzarella and put it in my little mini food processor along with the Panko and seasoning and gave it a few blends to break up the shreds of the “cheese”. Worked great.

    1. That was a wonderful idea, Lynne! Just out of curiosity, what’s your favorite brand of vegan shredded cheese? Thanks for taking the time to leave a comment and rating!!

  3. 5 stars
    Yum! I made this yesterday and have already eaten half of it by myself. Love that the squash is cut thinly (I used my mandoline) and the breadcrumb topping is great. I paired it with some penne a la vodka, and it was a delicious combination.

    1. The mandoline is totally the way to go, Amanda! I bet it tasted incredible with your pasta, too! Thanks so much for taking the time to leave a comment and rating! 🙂

  4. Hello, London.
    When carrying this dish to an event, would the recipe hold up better if I covered it with aluminum foil or with the plastic lid?
    Thank you.
    L

    1. Hi Laurie! Thanks for your quesiton. This casserole recipe is best served warm and preferably straight out of the oven so the topping still has a crunchy texture.  I would cover it with aluminum foil and then pop it into the oven before serving for about 10 minutes and then under a broiler for about 2 minutes to get the topping crispy again. Hope this helps!

    1. I wouldn’t recommend freezing this before cooking, Judy, as the squash and zucchini have a tendency to seep moisture when they are cut for too long. You could freeze it after cooking but the texture will definitely not be quite as good!

  5. 5 stars
    We make this often, love this recipe as written. Love being able to put together in advance, thanks for that tip! Making again today and trying with the vegan Parmesan cheese…..

    1. Yay! So happy you enjoy the recipe! I’d love to know how the vegan Parm works out for you and what kind you use! Thanks for the comment and rating 🙂

  6. 5 stars
    Very nice snack for my family of 3. I will make it again. The single rows are a great idea to balance the textures and make sure it’s not a mushy mess. Next time I’ll be making many more rows on a cookie sheet. I used what I had left in the fridge. It was only 2 zucchini and 1 squash which made 4 rows in a 8×11 casserole dish. Gonna stock up and double that when I make it.

  7. Excellent. I just sliced the squash and baked it UNcovered first. It allows the extra moisture to escape. Then add the other ingredients and bake UNcovered.