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:
- Layer the zucchini and yellow squash.
Alternate the zucchini and yellow squash in a 9-inch square baking dish. (Steps 1 and 2 above.)
- Sprinkle with remaining salt and pepper.
Lightly season the layered squash (Step 3 above.)
- Whisk together breadcrumbs, Parmesan cheese, and garlic powder.
Then evenly shake it over the zucchini and squash. (Step 4 above.)
- Cover baking dish with aluminum foil and bake in preheated 350° oven for 30 minutes.
It may take a few minutes more if the slices were cut thick, or less time if the slices are thin.
- Broil for 3-5 minutes.
Keep a close eye on it! The topping will crisp up and turn brown quickly.
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
Squash releases liquid while cooking. However, there is a trick to prevent this. Before cooking, sprinkle the squash with salt, let it sit for about 10 minutes, then blot it dry.
Yes you can! Zucchini is a member of the squash family, and goes wonderfully in many casserole recipes.
When it comes to Summer squash, no. In fact, leaving the skin on adds a nice color and texture to many dishes.
If your harvest comes in all at one time – squash and zucchini casserole is the answer! You can also sauté squash or roast it in the oven with other vegetables in this Italian Roasted Vegetables recipe.
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:
More healthy side dish recipes.
Healthy Summer Squash Casserole
Healthy, simple, and fabulous, this Zucchini and Squash Casserole is the best low-carb recipe for Summer squash! This easy casserole is amazing for Summer picnics and potlucks, and makes the perfect side dish for any holiday dinner!
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
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Preheat oven to 350 degrees.
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Cut yellow squash and zucchini into thin, ¼-inch slices.
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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.
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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.**
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Drizzle olive oil over the zucchini and squash and then sprinkle with salt and pepper.
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In a small bowl combine Parmesan cheese, breadcrumbs, and garlic powder. Toss to combine and then sprinkle over the zucchini and squash.
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Cover baking dish with aluminum foil and bake in preheated oven for 30 minutes.
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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.
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Serve immediately with fresh parsley and enjoy!
Recipe Video
Recipe Notes
*Can use a vegan Parmesan cheese substitute.
**I like to get small-medium, similarly-sized summer squash so they will be able to fit into four rows easily!
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 to soggy mess. Let the salted squash sit, then blot dry. The salt releases excess moisture.
- Try out Italian breadcrumbs. Since they’re pre-seasoned, 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.
Meal Prep and Storage
- 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 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.
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Debbie Reis says
Serving alongside Lasagna made by my daughters in-laws who are here visiting. Need something lite for those who can’t have so many carbs.
London says
What a great idea, Debbie! So happy you enjoyed the recipe. Thanks for your comment and rating 🙂
Kelli says
When do I add in the garlic powder?
With the breadcrumbs or when seasoning the squash…?
Thanks
London says
Sorry for any confusion, Kelli! You add the garlic powder with the breadcrumbs mixture. I’ve updated the recipe to reflect this. Thanks for the question!
Jen F. says
Can’t wait to try this recipe. BTW, the end of the squash that you cut off in the video was the stem end. The other side is called the blossom end. Cheers!
London says
Yay! Can’t wait for you to try it either. And great to know about the stem end 🙂 I had no idea it was called the blossom end either! Thanks for your comment and knowledge!
Vicki says
Hi London,
I am making a double batch. How long should I cook the casserole?
Thank You
Vicki
London says
Hi Vicki! You shouldn’t need to cook the casserole for more than about 5 additional minutes. Just make sure you’re making it in a large enough casserole dish. (A 13 x 9-inch should work great!) Can’t wait to hear what you think!
Mackenzie says
How long does this keep in the fridge once cooked?
London says
Hi Mackenzie! It will keep for up to 3-4 days, but does get a little soggier the more it sits. It’s best to reheat it in the oven for the best texture!
Anonymous says
Delicious. I’ll be making this again.
London says
Yay! So happy you enjoyed the recipe. Thanks for your comment and rating!
Linda says
This was soooooo much better than the boxed stuff! My boys loved it!
London says
Yay, Linda! I’m so happy you and the boys enjoyed the recipe. Thanks so much for your comment and rating! 🙂
Marty Davis says
This was absolutely delicious! My husband who does not love squash because it can get soggy, went back for seconds! I did put the salt on the squash and let it sit for 10-12 minutes to draw out the water. They turned out perfect and the topping stayed crunchy! No leftovers! Thanks for this awesome recipe!
London says
Yay, Marty!! I’m so happy to hear it passed the hubby’s seconds test! lol. Thanks so much for your comment and feedback! 🙂
Amanda says
I didn’t think to take a picture, but this recipe is amazing! I love squash casserole and this was a lighter alternative that was perfect for a 4th of July BBQ. I doubled the recipe, but we still didn’t have any leftovers and people were asking for the recipe. This will definitely be one of my easy go-to side dishes from now on!
London says
Yay, Amanda! So happy to hear it was a hit at your July 4th BBQ! Thank you so much for your comment and rating!
Sue says
The Dutch baby was perfect and delicious! Looking forward to trying more of your recipes!
London says
Hi Sue!! I am SO happy you enjoyed the Dutch baby pancake. What toppings did you add to it? Thanks so much for your comment!!