Cheesy Zucchini Casserole

If you ask me, zucchini casserole is one of those comfort dishes that never disappoints.

This cheesy, garden-fresh dish brings together layers of tender zucchini, savory herbs, and melted cheese in a way that makes everyone at the table happy. The vegetables stay firm enough to give the casserole substance, while the golden-brown top adds just the right finishing touch.

It’s the kind of recipe that turns summer’s abundance of zucchini into a dish that even vegetable skeptics enjoy. A sprinkle of breadcrumbs and a handful of fresh herbs make everything come together perfectly.

It’s a family-friendly meal that works just as well for weeknight dinners as it does for potlucks, and it’s especially good when zucchini is in season.

What Kind of Zucchini Should I Use?

For this casserole, medium-sized zucchini (about 6-8 inches long) are your best bet since they’re tender but still firm enough to hold their shape when cooked. Try to pick zucchini that feel heavy for their size and have smooth, blemish-free skin that’s dark green in color. Smaller zucchini tend to be sweeter and have fewer seeds, while really large ones can be watery and have tough seeds that might make your casserole soggy. When you’re at the store, give them a gentle squeeze – they should feel firm but not hard, and avoid any that feel spongy or soft.

Options for Substitutions

This casserole is pretty adaptable and you can make several swaps based on what you have in your kitchen:

• Roma tomatoes: Any medium-sized tomato variety will work here. You can even use cherry tomatoes (halved) or 2 cans of well-drained diced tomatoes if fresh ones aren’t in season.
• Zucchini: Yellow summer squash makes a perfect substitute, or try a mix of both! You could also use eggplant, though you’ll want to salt it first to remove excess moisture.
• Italian herbs: No Italian herb blend? Mix equal parts dried oregano, basil, and thyme. Fresh herbs work too – just triple the amount.
• Breadcrumbs: Try crushed crackers, panko, or even ground almonds for a low-carb option. Just toast them lightly first for better texture.
• Cheese options: Pecorino Romano works instead of Parmesan, and provolone or Monterey Jack can replace mozzarella. For a dairy-free version, try dairy-free cheese alternatives, though the texture will be slightly different.
• Fresh herbs: If you don’t have fresh parsley and basil, use dried herbs (about 1 teaspoon each) mixed into the breadcrumb topping instead of as a garnish.

Watch Out for These Mistakes While Baking

The biggest challenge when making zucchini casserole is dealing with excess moisture – zucchini releases a lot of water during cooking, which can make your casserole soupy instead of perfectly layered. To prevent this, try laying your sliced zucchini and tomatoes on paper towels for 15-20 minutes before assembling, and gently pat them dry to remove excess moisture. Another common mistake is rushing through the layering process – take your time to create even layers and make sure the vegetables slightly overlap, which helps the casserole hold together better when serving. For the crispiest top layer, avoid covering the casserole during the last 10 minutes of baking, and if your breadcrumb topping starts browning too quickly, simply place a piece of foil loosely on top. To ensure the best texture, let the casserole rest for 5-10 minutes after baking – this helps the cheese set and makes it easier to portion out clean, beautiful servings.

What to Serve With Zucchini Casserole?

This cheesy zucchini casserole works great as a side dish, but you can also make it the star of the show with some tasty accompaniments. For a light summer dinner, serve it alongside some grilled chicken or fish – the Italian herbs in the casserole pair really nicely with lemon-seasoned proteins. If you’re keeping things vegetarian, try serving it with a fresh arugula salad dressed simply with olive oil and lemon juice, or pair it with some crusty French bread to soak up all those nice tomato juices. Since this dish already has lots of vegetables, you might just want to add some fluffy rice or quinoa to round out the meal.

Storage Instructions

Keep Fresh: This yummy zucchini casserole will stay good in the fridge for up to 4 days when stored in an airtight container. The flavors actually get even better after a day or two as everything melds together nicely. It’s perfect for making ahead for busy weeknight dinners!

Freeze: You can freeze this casserole for up to 3 months in a freezer-safe container. Just keep in mind that the zucchini might release a bit more water when thawed, but it’ll still taste great. I like to portion it into individual servings before freezing for easy grab-and-go meals.

Reheat: To warm up your casserole, pop it in the oven at 350°F for about 20 minutes, or until heated through. If using the microwave, heat in 1-minute intervals, stirring between each. To help keep the topping crispy when reheating, you can sprinkle on a few fresh breadcrumbs before warming.

Preparation Time	15-20 minutes
Cooking Time	45-50 minutes
Total Time	60-70 minutes
Level of Difficulty	Easy

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 600-700
• Protein: 25-30 g
• Fat: 40-50 g
• Carbohydrates: 40-45 g

Ingredients

• 1 pound roma tomatoes (cut into 1/4-inch slices)
• 1 ½ pounds zucchini (cut into 1/2-inch slices)
• 1/2 teaspoon italian herbs
• 1 ½ tablespoons olive oil
• 1 minced garlic clove
• Salt and pepper for seasoning
• Chopped fresh parsley and basil for serving
• 1 tablespoon olive oil
• 1/2 onion (finely diced)
• 1/4 cup breadcrumbs
• 2 tablespoons butter, melted
• 1/4 cup grated parmesan cheese
• 2/3 cup grated mozzarella cheese

Step 1: Prepare Ingredients

Start by preheating the oven to 375°F.

While the oven is heating, cook the onion in olive oil over medium heat until tender, about 5 minutes.

Set the cooked onion aside to cool.

Next, slice the tomatoes and place them on paper towels to absorb excess liquid, about 2 to 3 minutes.

Step 2: Season and Assemble Vegetables

In a bowl, combine zucchini slices with Italian seasoning, olive oil, and minced garlic.

Toss the zucchini well to ensure it is evenly coated, then season with salt and pepper to taste.

Create alternating stacks of zucchini and tomato slices and place these stacks on their sides in a 2 ½ quart baking dish or a 9×13 inch pan.

Step 3: Initial Baking

Cover the baking dish with foil to trap steam and help cook the vegetables evenly.

Place the dish in the preheated oven and bake for 25 minutes, allowing the zucchini and tomatoes to tenderize.

Step 4: Prepare Topping

While the vegetables are baking, prepare the topping.

Combine the onions you set aside with any additional topping ingredients of your choice in a small bowl.

Mix thoroughly to ensure the flavors are well combined.

Step 5: Add Topping and Final Baking

After 25 minutes of baking, remove the foil from the casserole dish.

Evenly distribute the topping mixture over the zucchini and tomatoes.

Return the dish to the oven and bake uncovered for an additional 20 minutes, or until the zucchini is tender and the topping is golden.

Step 6: Garnish and Serve

Once done, remove the dish from the oven and let it cool slightly.

Sprinkle with fresh herbs of your choice for added flavor and aroma.

Serve the dish warm and enjoy!