Zucchini Squash Casserole

This easy-to-make zucchini squash casserole is a flavorful combination of tender, tasty summer squash and creamy, cheesy sauce. Top it all off with crunchy Panko breadcrumbs for an incredible veggie side dish everyone loves.

Jump to:

• ❤️ Why I Love This Recipe
• 🥘 Ingredients
• 📖 Variations
• 🧂 Substitutions
• 🔪 How To Make Zucchini Squash Casserole
• 💭 Angela's Pro Tips & Recipe Notes
• 🥡 Storing & Reheating
• 🍽️ Serve With
• 📖 Recipe Card
• 💬 Comments & Reviews

Trying to trick yourself (or your kids) into eating more vegetables? Then try this tasty zucchini and squash casserole that non-veggie AND veggie lovers will all love.

Thinly sliced zucchini and yellow squash are mixed with a delicious homemade cheese sauce and then baked to perfection.

The mild flavors of the zucchini and squash are covered in a delicious garlic and cheese sauce and sprinkled with the perfect crunchy topping.

The combination is an amazingly flavor-filled dish that you will forget is mostly veggies! Personally, I could easily eat a hearty serving as my entire dinner!

❤️ Why I Love This Recipe

Super Easy. When you realize how easy it is to make a homemade cheese sauce with some basic kitchen staples, you will want to experiment with using it on lots of other veggies.

Tasty. This creamy, cheesy sauce is full of flavor and will seriously make you forget you are eating not one, but two different vegetables. It’s so good, your kiddos may just ask for seconds.

Versatile. Swap the seasoning, cheese types (just make sure to use a good melting cheese), or veggies to create a personalized side dish.

🥘 Ingredients

If you don’t already use Italian herbs and Panko breadcrumbs, you’ll love making them new staples in your pantry. Most of the other zucchini squash casserole ingredients are common kitchen staples.

• Zucchini - Zucchini is a green squash that is very versatile. It has a mild flavor and does not have seeds you have to remove, which makes it extremely easy to cook with.
• Yellow Squash – Yellow squash is another summer squash (squash with thin, edible skin). Like zucchini, it has a mild flavor and takes on the flavors its cooked with.
• Butter – Salted butter will give you the best flavor in this recipe, as it is used to create the base for the cheese sauce.
• All-Purpose Flour – AP flour is combined with the butter to make a roux that helps thicken the sauce.
• Garlic – Garlic is a great flavor enhancer with a unique flavor. You can chop up fresh garlic or use the jarred minced garlic.
• Whole Milk – Whole milk is important for this recipe because it provides a little bit of fat that helps thicken the sauce.
• Italian Herbs (Italian Seasoning) – Common Italian herbs are dried basil, dried oregano, dried rosemary, dried thyme, dried marjoram, and sometimes sage. Italian Seasoning is a combination of these herbs and the easiest way to get the best balance of flavors.
• Cheddar Cheese – Grated cheese is best for this recipe, as it will melt the easiest when added to the sauce base.
• Panko Breadcrumbs - These breadcrumbs are used as a topping to add an extra “crunch” to the casserole. If you don't have any use my recipe to make your own.
• Salt and Pepper – Begin slowly and taste the sauce as you go.

📖 Variations

Broccoli and cauliflower – Replace the zucchini and yellow squash with broccoli and cauliflower. Rinse the broccoli and cauliflower and cut into individual florets. Follow the same directions to prepare the sauce and bake the casserole as above.

Potatoes – It’s not quite a green vegetable dish, but you can make this into a delicious creamy and cheesy potato side dish! Wash, peel, and cut 6 medium potatoes into 1-inch chunks. Follow the same directions to prepare the sauce and bake the casserole as above.

🧂 Substitutions

Heavy cream or Half & Half. To make a truly indulgent sauce, substitute either heavy cream or half and half for the whole milk.

Gluten Free Sauce. If you are gluten-sensitive you can use corn starch to thicken the sauce instead of the flour.

🔪 How To Make Zucchini Squash Casserole

Follow these super easy instructions to get an amazing veggie dish on the table that the whole family will love.

Make the Sauce

1. Preheat. Set your oven to 375°F (190°C) and lightly butter or grease your cast iron skillet or baking dish.
2. Prepare vegetables. Wash 3 each zucchini and yellow squash then slice into rounds about ¼ inch thick. Arrange the zucchini and squash in a cast iron pan or baking dish.
3. Sauté the garlic. Next, in a large skillet over medium heat melt 4 tablespoons butter and saute 1 tablespoon of minced garlic for a 1-2 minutes.
4. Make the roux. Add ¼ cup flour and whisk into the melted butter and garlic.
5. Whisk in the milk. Slowly start adding 2 cups of milk and whisk into the butter and flour mixture. Continue adding the milk while whisking until the mixture is smooth with no lumps.
6. Season and melt cheese. Reduce heat and stir in 1 tablespoon of Italian herbs, 2 cups of grated cheese, salt, and pepper (to taste). Whisk or stir until all the cheese has melted. Remove from heat.

Assemble the Casserole

1. Mix sauce with vegetables. Pour the melted cheese mixture over the arranged zucchini and squash. Top with ½ cup of Panko breadcrumbs.
2. Bake until golden. Place in the middle of your oven's center rack and cook at 375°F (190°C) for 50 minutes or until the top has browned sufficiently.
3. Serve. Remove from the oven and allow to cool slightly before serving.

If serving your zucchini squash casserole alongside another dish, cover with foil when you remove it from the oven and let it sit on top of the oven to keep it warm until you are ready to serve it. Enjoy!

💭 Angela's Pro Tips & Recipe Notes

• Get all the flour combined with the butter first. The base of this cheese sauce is a roux that is made from combining butter and flour. It’s important to get all the flour and butter combined, before adding the milk. Be sure to cook the roux for 1-2 minutes to cook off the flour flavor (before adding the milk).
• Take your time adding the milk. To get the sauce as smooth as possible, take your time adding in the milk. I suggest measuring the milk into a an easy to pour cup. Slowly pour a little at a time into the pan as you whisk it together with the roux. A whisk is an important kitchen tool to use, as it will help you get a smooth sauce.

🥡 Storing & Reheating

Simply cover your dish with a lid or plastic wrap, or transfer it to an airtight storage container, to save any leftovers.

Your leftovers can be refrigerated for up to 3-4 days in the refrigerator. I find, however, that the veggies are best if enjoyed with 1-2 days.

Reheating

Your veggie casserole is best reheated in the oven. I even like to add some extra Panko breadcrumbs on top to add some more crunch to the leftovers.

🍽️ Serve With

This casserole is the perfect addition to a delicious baked or grilled chicken. Try it with one of these easy and delicious chicken recipes!

• Baked BBQ Chicken Breast
• Instant Pot Chicken Thighs
• Baked Chicken Quarters
• Shake and Bake Chicken
• Hasselback Chicken

📖 Recipe Card