Cheesy Zucchini Casserole Recipe (Easy to Make)

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!

A casserole dish with wooden spoon dishing up a portion of zucchini casserole.

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Why You Will Love Making Zucchini Casserole

  • We all love recipes that don’t have us tied to the kitchen for hours. One of the best things about this zucchini casserole is how straightforward it is. You’ll be layering and baking in no time, with minimal fuss. And that creamy sauce with melted cheese? It sounds delicious because it is – and yet, it’s so simple to put together!
  • Got a few zucchinis lying around? Maybe your garden produced a bountiful harvest this season. This casserole is a fabulous way to use up all that extra zucchini. It transforms those humble green squashes into a mouth-watering dish that’ll have everyone asking for seconds.
  • Whether you’re hosting a summer BBQ, a cozy winter gathering, or even a Sunday family lunch, this zucchini casserole never disappoints. It’s a fantastic side dish, but with its rich flavors and satisfying textures, it can easily stand as the main event. Even those who aren’t usually fans of zucchini find themselves drawn to its cheesy allure.
  • Apart from being utterly delectable, this dish is packed with the goodness of zucchini. We’re talking about a low-calorie veggie rich in vitamins, minerals, and antioxidants. Paired with the protein of cheese and the wonderful flavors from Italian seasoning and other fresh herbs, it’s a dish that feels indulgent but is still kind to your waistline. It is the BEST zucchini casserole recipe!
  • Gluten-free? Keto? No problem! With just a few tweaks, like using gluten-free breadcrumbs or opting for low-carb breadcrumbs, this zucchini gratin can easily be adapted to suit various dietary needs without sacrificing flavor.

Ingredients You’ll Need

You’ll need all the ingredients shown in the photograph below.

Ingredients for a zucchini casserole.

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!

Zucchini slices in a colander on a table.
Slice and place the zucchini slices in a lined colander, sprinkle with salt, and let sit for 45 minutes.

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.

A bowl with ingredients for a zucchini casserole.
Add onion, eggs, and cheese to a bowl.
A bowl with eggs, flour and other ingredients.
Mix to combine.

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.

Layering and Baking

Grab your prepared baking dish (remember to give it a little spray with non-stick cooking spray first!).

Place your sliced zucchini in overlapping layers, and pour over the cheesy mixture so the zucchini is well-covered.

Sliced zucchini in a baking dish.
Place the zucchini slices in a prepared baking dish.
A baking dish of unbaked casserole.
Pour the cheesy mixture over the slices.
A casserole dish filled with zucchini and cheese.
Bake uncovered for 20 minutes.

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.

A casserole dish filled with zucchini casserole.
Remove from the oven, and scatter the cheese and breadcrumb over the top.
A casserole dish filled with baked zucchini casserole.
Return to the oven and back for 20 minutes until golden brown.

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!

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.
Zucchini casserole on a white plate with a fork.

How to Store Leftover Zucchini Casserole

Once cooled, transfer the casserole to an airtight container. If you don’t have a suitable container, you can also cover your casserole dish or baking dish tightly with plastic wrap or aluminum foil.

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!

A person holding a casserole dish with zucchini casserole.

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.

The grains soak up the creamy sauce from the casserole, ensuring you get a burst of flavor with every bite.

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.

Cheesy zucchini casserole on a plate with a fork.

More zucchini recipes to try

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Cheesy Zucchini Casserole Recipe (Easy to Make)

With its creamy sauce, melted cheese, and perfectly baked zucchini, this Zucchini Casserole will surely win over even the pickiest eaters!
Prep Time25 minutes
Cook Time40 minutes
Total Time1 hour 5 minutes
Servings8 servings
Calories196
Course: Side Dish
Cuisine: American

Ingredients

  • 4 medium Zucchini sliced into ¼" slices
  • 1 sprinkle Salt this is a very light sprinkle
  • 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 tsp Italian seasoning
  • Salt and pepper to taste
  • 1 cup Panko breadcrumbs
  • 2 tbsp Butter melted

Instructions

  • Preheat your oven to 375°F/190°C. Grease a 1½ 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 sprinkle 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 tsp 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 tbsp 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. Remove from the oven, serve and enjoy!
    1 cup Sharp Cheddar cheese

Notes

  1. 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.
  2. 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.
  3. Gluten-Free Zucchini Casserole: To make this recipe gluten-free, simply swap out the Panko breadcrumbs for a gluten-free alternative.
  4. 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!
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. 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.
  11. 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

Calories: 196kcal | Carbohydrates: 11g | Protein: 11g | Fat: 13g | Saturated Fat: 7g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 3g | Trans Fat: 0.1g | Cholesterol: 72mg | Sodium: 387mg | Potassium: 329mg | Fiber: 2g | Sugar: 4g | Vitamin A: 591IU | Vitamin C: 18mg | Calcium: 256mg | Iron: 1mg

Disclaimer

Please note that nutrient values are estimates only. Variations can occur due to product availability and manner of food preparation. Nutrition may vary based on methods of origin, preparation, freshness of ingredients, and other factors.

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Recipe Rating




13 Comments

  1. 5 stars
    This zucchini casserole was an absolute delight! The way it combines the freshness of zucchini with creamy, cheesy goodness is a true comfort food masterpiece. One of the best ways to make use of garden-fresh zucchinis. Thanks for sharing this recipe.

  2. 5 stars
    I made this recipe recently, and everyone loved it at our family get-together. It was super tasty and super easy to make. My mom even asked for the recipe!

    1. That’s fantastic to hear! It’s wonderful when delicious dishes also bring loved ones together.

  3. 5 stars
    My grandma used to make a zucchini casserole I loved and this one came out so similar to hers! It was nostalgic for me. I’ll definitely be making it again!

    1. That’s such a heartwarming connection! I’m thrilled to hear that this zucchini casserole brought back fond memories of your grandma’s cooking. Keep making and savoring this dish.

  4. 5 stars
    Zucchini is one of my favorite veggies, but I haven’t really tried it in a casserole before. This dish was a hit!!! Creamy, cheesy, crunchy, but I can still taste the freshness of the zucchini! It was so comforting, and will definitely make this again this Thanksgiving!

    1. I’m so glad to hear that you enjoyed the zucchini casserole! It’s a fantastic choice for Thanksgiving!

  5. 5 stars
    I made the Zucchini Casserole from this recipe, and it’s a hit! The creamy sauce and melted cheese perfectly complement the baked zucchini. A crowd-pleaser for sure, even with picky eaters like my son!

  6. 5 stars
    made this with gluten-free breadcrumbs and it was such a decadent treat of a side dish! Happy to have a good casserole back in the rotation, they’re often so heavy and way too indulgent for my taste but this one was perfect!

    1. It’s great to hear that you enjoyed this casserole with gluten-free breadcrumbs! Enjoy having it in your rotation!

  7. 5 stars
    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…