Cheesy Zucchini Casserole Recipe (Easy to Make)
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Whether you’re looking for a quick and easy side dish for your next summer barbecue or a standout centerpiece for your vegetarian holiday feast, this Zucchini Casserole recipe has got you covered. With its creamy sauce, melted cheese, and perfectly baked zucchini, this is a dish that’s sure to win over even the pickiest eaters!
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I love making this zucchini casserole because it’s quick, comforting, and a smart way to use up extra zucchini. The creamy, cheesy layers come together easily and work for any occasion, from a casual dinner to a cookout. Even picky eaters end up enjoying it, and it’s easy to tweak for gluten-free or low-carb needs without losing flavor.
Ingredients You’ll Need
You’ll need all the ingredients shown in the photograph below.
How to Make Zucchini Casserole with Step-by-Step Instructions
A complete printable recipe and the measurements in both US customary and metric are available in the recipe card below.
Preparing Your Zucchini Slices
Preheat the oven to 375°F (or 190°C).
Then, slice your zucchini and place them in a colander lined with kitchen paper. Sprinkle them lightly with some salt and set them over the sink. This little trick helps to draw out any excess moisture – nobody wants a watery casserole!
I line mine with reusable Swedish dishcloths that soak up moisture really well and don’t shred like paper towels.
You can let them sit for at least 15 minutes, but half an hour or a little longer is ideal.
After about 30 to 45 minutes, blot them dry with a kitchen towel or paper towel. You’ll be amazed at how much water they release!
Whipping Up the Cheese Sauce
In a large bowl with a wooden spoon, combine the onion, eggs, a mix of Cheddar cheese and mozzarella cheese, and, of course, a sprinkle of vegetarian Parmesan.
For that extra punch of flavor, add some Italian seasoning, a pinch of garlic salt, and season with black pepper.
Mix it all up until everything is well combined. If it seems a little thin, don’t worry! The sauce thickens up as it cooks. A silicone spatula is perfect here—it scrapes every last bit out of the bowl without scratching it.
Layering and Baking
Grab your prepared baking dish (remember to give it a little spray with non-stick cooking spray first!). I use a 9×13 ceramic casserole dish that bakes evenly and looks nice enough to go straight from oven to table.
Place your sliced zucchini in overlapping layers, and pour over the cheesy mixture so the zucchini is well-covered.
Bake uncovered for about 20 minutes. While that’s happening, in a small bowl, prepare the golden topping with Panko breadcrumbs, melted butter, and more Parmesan cheese.
Once the 20 minutes are up, sprinkle this breadcrumb mixture on top, add a bit more cheddar, and bake until it turns golden brown. Voila!
If you’re taking this to a potluck or family gathering, I highly recommend sliding your dish into this Reusable Insulated Casserole Carrier. It keeps everything warm without spills, and honestly, it’s saved me more than once when I’ve had to transport a hot dish in the car.
Equipment
Ingredients
- 4 medium zucchini sliced into ¼" slices
- 1 pinch salt
- ½ cup onion finely chopped
- 2 eggs slightly beaten
- 1 cup sharp Cheddar cheese shredded and divided
- ½ cup mozzarella cheese shredded
- ½ cup vegetarian Parmesan cheese plus 2 additional tablespoons finely grated
- 2 teaspoons Italian seasoning
- Salt and pepper to taste
- 1 cup Panko breadcrumbs
- 2 tablespoons butter melted
Video
Instructions
- Preheat your oven to 375°F (190°C). Grease a 1 ½ quart casserole dish and set aside.
- Place the sliced zucchini in a colander lined with kitchen paper over the kitchen sink, lightly sprinkle with salt, and let it sit for a minimum of 15 minutes, but preferably 30 – 45 minutes. Transfer the zucchini slices to a dry kitchen towel or paper, and blot the slices dry as much as possible, then set aside.4 medium zucchini, 1 pinch salt
- In a large mixing bowl, combine onion, eggs, Cheddar cheese, mozzarella cheese, vegetarian Parmesan cheese, Italian seasoning, and salt and pepper to taste.½ cup onion, 2 eggs, 1 cup sharp Cheddar cheese, ½ cup mozzarella cheese, ½ cup vegetarian Parmesan cheese plus 2 additional tablespoons, 2 teaspoons Italian seasoning, Salt and pepper
- Place the zucchini in overlapping layers and pour over the cheesy mixture so the zucchini are covered.
- Bake uncovered for 20 minutes. Add Panko breadcrumbs to a small mixing bowl while it's baking, and pour over the melted butter, along with the additional vegetarian Parmesan cheese, and stir until it is fully combined.1 cup Panko breadcrumbs, 2 tablespoons butter
- Remove the casserole from the oven, sprinkle the breadcrumb mixture evenly over the top, and scatter the remaining shredded Cheddar cheese. Baked until the cheese has melted and is bubbling and the top is golden brown approximately 20 minutes.1 cup sharp Cheddar cheese
- Remove from the oven, serve and enjoy!
Notes
- Zucchini: When shopping for zucchini, opt for medium-sized ones that feel firm to the touch. Big zucchinis might seem like a good deal, but they tend to be more watery and less flavorful. Those fresh zucchini with a bright green hue are the best bet for a vibrant and delicious casserole.
- Switching Things Up with Yellow Squash: While zucchini is the star of this recipe, you can totally mix things up by adding in some yellow squash (also called summer squash). It has a similar texture and moisture content, plus, the mix of green and yellow adds a delightful splash of color to the dish.
- Gluten-Free Zucchini Casserole: To make this recipe gluten-free, simply swap out the Panko breadcrumbs for a gluten-free alternative.
- Keto Zucchini Casserole: If you’re on a keto journey, replace the breadcrumbs with crushed keto breadcrumbs for a crispy, low-carb topping. It makes a delicious low-carb side dish!
- What’s the best way to slice the zucchini?: For this recipe, using a mandoline slicer will give you consistent, thin slices. If you don’t have one, a sharp knife will do the trick—just aim for uniform thickness. Thick slices take longer to cook, so thinner is better for this wonderful dish.
- Can I add other veggies to the casserole? Of course! Feel free to mix in some bell peppers, mushrooms, or even some spinach for added flavor and nutrition.
- Breadcrumbs: If you don’t have panko breadcrumbs, regular breadcrumbs will work just fine. They may offer a slightly different texture but will still give a lovely crunch to your casserole.
- Add a little heat: This recipe leans on the milder side. However, if you’re after some heat, you can add some red chili flakes or diced jalapeños to the mix.
- Storage: Once cooled, transfer the zucchini casserole to an airtight container. If you don’t have a suitable container, you can also cover your baking dish tightly with plastic wrap or aluminum foil. Your leftover zucchini casserole will stay tasty and fresh in the refrigerator for up to 3-4 days.
- Freeze: You can freeze your casserole too! Before doing so, wrap it tightly to prevent freezer burn, and it will stay good for up to 2 months.
- Reheat: When you’re ready to enjoy your casserole again, if it’s frozen, allow it to thaw overnight in the refrigerator. For reheating, pop it in a preheated oven at 375°F (190°C) until it’s hot and bubbly. If you’re in a hurry, individual portions can also be warmed up in the microwave. But for that delightful crispy top, the oven is your best bet!
Nutrition
Recipe Notes and Expert Tips
- Zucchini: When shopping for zucchini, opt for medium-sized ones that feel firm to the touch. Big zucchinis might seem like a good deal, but they tend to be more watery and less flavorful. Those fresh zucchini with a bright green hue are the best bet for a vibrant and delicious casserole.
- Switching Things Up with Yellow Squash: While zucchini is the star of this recipe, you can totally mix things up by adding in some yellow squash (also called summer squash). It has a similar texture and moisture content, plus, the mix of green and yellow adds a delightful splash of color to the dish.
- Gluten-Free Zucchini Casserole: To make this recipe gluten-free, simply swap out the Panko breadcrumbs for a gluten-free alternative.
- Keto Zucchini Casserole: If you’re on a keto journey, replace the breadcrumbs with crushed keto breadcrumbs for a crispy, low-carb topping. It makes a delicious low-carb side dish!
- What’s the best way to slice the zucchini?: For this recipe, using a mandoline slicer will give you consistent, thin slices. If you don’t have one, a sharp knife will do the trick—just aim for uniform thickness. Thick slices take longer to cook, so thinner is better for this wonderful dish.
- Can I add other veggies to the casserole? Of course! Feel free to mix in some bell peppers, mushrooms, or even some spinach for added flavor and nutrition.
- Breadcrumbs: If you don’t have panko breadcrumbs, regular breadcrumbs will work just fine. They may offer a slightly different texture but will still give a lovely crunch to your casserole.
- Add a little heat: This recipe leans on the milder side. However, if you’re after some heat, you can add some red chili flakes or diced jalapeños to the mix.
- Make it creamier: Want to make the sauce extra creamy? Add 2-4 tablespoons of sour cream, heavy cream, or plain Greek yogurt.
How to Store Leftover Zucchini Casserole
Once cooled, transfer the casserole to an airtight container. If you don’t have one handy, just wrap the whole casserole dish tightly in foil or stretchy silicone covers—they’re reusable and work like a charm.
For short-term storage, your baked zucchini casserole will stay tasty and fresh in the refrigerator for up to 3-4 days.
Planning ahead? You can freeze zucchini casserole too! Before doing so, wrap it tightly to prevent freezer burn, and it will stay good for up to 2 months. Just remember to label it with the date so you can keep track!
When you’re ready to enjoy your zucchini squash casserole again, if it’s frozen, allow it to thaw overnight in the refrigerator.
Pop it in a preheated oven at 375°F (190°C) for reheating until it’s hot and bubbly. If you’re in a hurry, individual portions can also be warmed up in the microwave. But for that delightful crispy top, the oven is your best bet!
What to Serve with Zucchini Casserole
From light salads to a holiday feast, zucchini casserole is te perfect side dish and pairs with the most delicious dishes.
Salads That Shine
If you’re looking to balance the creamy, rich texture of the zucchini casserole, a crisp salad is the way to go. Try our Waldorf Salad, Caprese Salad, Avocado Salad, or our Beetroot and Grilled Halloumi Salad which is perfect for a cookout!
Grain Goodness
For those who love a hearty meal, pairing your easy zucchini casserole with some wholesome grains is a match made in heaven.
Quinoa, brown rice, cilantro lime rice, or even a lovely couscous salad can add a satisfying, earthy element to your meal.
Bread, Glorious Bread
Can you think of anything better than a slice of crusty bread to go with your casserole? Whether it’s garlic-infused naan bread, a simple flatbread, focaccia, or even some gluten-free options, bread is perfect for mopping up the delicious, cheesy sauce.
If you’re feeling adventurous, you can even make some homemade garlic bread. Just spread some butter mixed with minced garlic and fresh herbs on your favorite loaf and toast till it’s golden brown. Yum!
Holiday Feast
This is a great recipe to add to your festive menu! Pair it with roasted root vegetables like honey-roasted carrots, Air Fryer Brussels Sprouts, and Creamy Mashed Potatoes.
A cranberry and walnut salad on the side adds a tangy, sweet crunch to the mix. And for the main event?
How about a centerpiece of an Air Fryer Nut Loaf, Lentil Loaf, or Vegan Ham? Finish off with some warm rolls, and you’ve got yourself a vegetarian feast that even the most avid meat lovers will be reaching for seconds.
More zucchini recipes to try
If you’ve got more zucchini than you know what to do with, then why not try these easy recipes?
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So, I’m not a big fan of zucchini. And I really don’t like hot zucchini. I mean, I’ll eat it, but it’s so not my fav. But my daughter LOVES it. And, if you’re a mid-life momma and your kiddo is coming to visit, you make her favorites even if you’re not a fan of zucchini. OMG, I LOVED this dish! The panko gave it a nice crunch (which got me past my usual complaint about baked zucchini being too mushy) and the cheese was, well, what is NOT better with cheese? Go ahead, I’ll wait while you think of something…