Healthy, simple, and fabulous, this Zucchini and Squash Casserole is the best healthy 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!
Simple Summer Squash Casserole
Zucchini and yellow squash are some of the overlooked vegetables that somehow magically reappear during the summer months and at a Thanksgiving dinner table.
I first discovered my love of cooking with this delightful combo when I ended up with enormous bags full of fresh summer produce from a friend.
After making a few batches of this Sautéed Zucchini and Squash, I started to run out of recipe ideas.
It would have been a sin to let all those healthy veggies go bad, so I had to brainstorm a new summer recipe.
Summer squash casserole has always been one of my favorite summertime side dishes. But, it’s usually full of not-so-healthy ingredients like sour cream and Ritz crackers. (I love those buttery crackers, but there’s a time and a place for them.)
This time, I channeled that bounty of produce into a healthier version of the traditional casserole. I decided to transform it into something simple to make, baked in the oven, and a sure-fire family favorite.
And the results were a crispy, flavorful, healthy side dish that held its own against the original recipe. Once you make this classic Southern recipe with fresh yellow squash and zucchini, you’ll wonder where it’s been your whole life.
Ingredients
The ingredients to make this best squash casserole are pretty simple:
- 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 healthy 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
- Parsley. Not absolutely necessary but it makes the casserole really pretty when serving. You can also use fresh thyme or other herbs you love.
How to Make Squash Casserole
Below, you’ll find the simple steps to make this summer squash casserole recipe at home:
Prep the Squash
To get the Summer squash ready to bake, there are a few things to do.
First, you need to slice the fresh squash into uniform pieces. You can either use a mandolin (if so be very careful with your fingers!), or you can thinly slice them by hand.
You want them to be ¼-inch thick. If they end up thicker, they 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 excess liquid they typically retain. It will help you to get a crispy, and not soggy, casserole.
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.
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.
Can you freeze squash casserole?
Yes, you can definitely freeze squash casserole. However, be sure to let it cool completely. Then, cover the pan in plastic wrap so little to no air is coming into contact with the casserole. It should keep in the freezer for up to 2 to 3 months.
Can you make summer squash casserole ahead of time?
Yes, it is easy to prep summer squash casserole ahead of time. Follow all directions but wait to bake until you’re ready to serve. Cover tightly with foil or prepare in an airtight container and refrigerate for up to 2 days. Bring to room temperature and bake according to directions.
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.
Expert Tips and Tricks
- Use a mandolin. This gives you the most precise slices so they all cook at a similar rate.
- Sprinkle first. A little salt will help prevent a soggy mess. Let the salted squash sit, then blot dry. The salt draws out excess moisture.
- Add some flavor. 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. It’s okay to use all zucchini or all yellow squash if that’s what you have.
What to Serve with Squash Casserole?
This dish is an excellent side for healthy 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 Salmon, Lemon Garlic Baked Salmon or Air Fryer Salmon.
Other Squash Recipes
If you like the best yellow squash casserole, make sure to check out these other easy and healthy recipes.
Baked Parmesan Zucchini Fries and Crispy Zucchini Fritters are so good, you’ll forget they’re good for you.
Zucchini Lasagna Roll-Ups are the perfect Italian-style main dish.
Sautéed Zucchini and Squash is a quick and easy side.
And don’t forget to check out How to Make Zucchini Noodles.
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Ingredients
- 2 lbs. summer squash zucchini and yellow squash, cut into ¼-inch slices
- 2 ½ Tbsp. olive oil
- 1 ¼ tsp. salt divided
- ½ tsp. pepper
- ⅓ cup Parmesan cheese* grated
- ⅓ cup Panko breadcrumbs gluten-free
- ¼ tsp. garlic powder
- 2 Tbsp. fresh parsley finely chopped
Instructions
- Preheat oven to 350 degrees.
- 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.
- Spray a 9-inch square baking dish with non-stick cooking spray.
- Alternatively, overlap the zucchini and squash in a row. (See pictures.) 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.
- 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!
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Notes
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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?
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!
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.
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!!
Violife and Whole Foods 365 brand
Wonderful! I’ll have to look for those next time at the store 🙂
Where is the olive oil used did not see it in directions
It’s listed in Step 6 of the recipe 🙂
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.
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! 🙂
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
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!
Can this be prepared and then frozen to be cooked later?
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!
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…..
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 🙂
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.
Yay! So happy you enjoyed the recipe, Christina! Thanks for the comment and rating! 🙂
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.
What a great idea, Kas – will definitely have to try that out!
See nutrition facts,But I don’t know how many servings for a recipe.
Hi Stephanie! There are 6 servings in this casserole recipe. Hope you enjoy 🙂