Name: Baked Zucchini Spinach and Feta Casserole Recipe
Prep time: 20 min
Cook time: 35 min
Total time: 55 min
Ingredients: 3 medium zucchini, thinly sliced into half moons; 4 cups fresh spinach, roughly chopped and packed; 1 small yellow onion, finely diced; 3 cloves garlic, minced; 2 stalks green onions, thinly sliced (optional, for topping); 1 cup feta cheese, crumbled; 1 cup shredded mozzarella or low-moisture provolone; 1/2 cup grated Parmesan cheese; 4 large eggs; 3/4 cup whole milk or half and half; 2 tablespoons plain Greek yogurt or sour cream; 2 tablespoons olive oil, plus more for greasing and drizzling; 1/4 cup fine breadcrumbs or panko; 2 tablespoons all-purpose flour; 1 teaspoon kosher salt, plus more to taste; 1/2 teaspoon freshly ground black pepper; 1 teaspoon dried oregano; 1/2 teaspoon dried basil; 1/4 teaspoon crushed red pepper flakes (optional); 1 lemon, zested (optional); 2 tablespoons chopped fresh parsley or dill, for garnish (optional)

Baked Zucchini Spinach and Feta Casserole Recipe tastes creamy, cheesy, and herby with a golden top and tender veggies in every bite. It works perfectly for busy weeknights or relaxed weekend brunch and takes about 55 minutes from start to finish. I tested this version on my own picky family, and they went back for seconds without asking what vegetables I hid inside.

Why You Should Try This Baked Zucchini Spinach and Feta Casserole Recipe

This casserole packs a lot of flavor into simple ingredients: sweet zucchini, earthy spinach, salty feta, and a touch of garlic and herbs. The eggs and a bit of dairy hold everything together so you get a sliceable, satisfying dish that still feels light.

It fits gluten free and vegetarian needs with easy swaps, and you can prep it ahead for meal prep or entertaining. I like it as a main dish with a salad, but it also works as a side next to grilled chicken or fish.

“This Baked Zucchini Spinach and Feta Casserole Recipe tastes like summer in a baking dish and makes veggies disappear from plates in record time. ★★★★★”

Ingredients You’ll Need

Fresh produce

3 medium zucchini, thinly sliced into half moons
- Choose firm zucchini with shiny skin and few seeds.
4 packed cups fresh spinach, roughly chopped
- Baby spinach wilts quickly and tastes mild.
1 small yellow onion, finely diced
3 cloves garlic, minced
2 green onions, thinly sliced (optional, for topping)

Dairy and eggs

1 cup crumbled feta cheese
- I like sheep’s milk feta in brine for stronger flavor; pre-crumbled works if you want a shortcut.
1 cup shredded mozzarella or low moisture provolone
- Use part skim for a lighter casserole or whole milk for extra richness.
½ cup grated Parmesan cheese
4 large eggs
¾ cup whole milk or half and half
- You can use 2% milk if needed; the texture stays tender but slightly lighter.
2 tablespoons plain Greek yogurt or sour cream
- This adds tang and creaminess without heavy cream.

Pantry items

2 tablespoons olive oil
¼ cup fine breadcrumbs or panko
- Use gluten free breadcrumbs if you want a gluten free version.
2 tablespoons all purpose flour
- Swap with a 1:1 gluten free blend if needed.
1 teaspoon kosher salt, plus more to taste
½ teaspoon freshly ground black pepper
1 teaspoon dried oregano
½ teaspoon dried basil
¼ teaspoon crushed red pepper flakes (optional, for a little heat)

Optional flavor boosters

Zest of 1 lemon
2 tablespoons chopped fresh parsley or dill for garnish

Equipment

9×13 inch baking dish or similar size casserole dish
Large skillet or sauté pan
Large mixing bowl
Whisk
Cutting board and sharp knife
Box grater (if you shred your own cheese)
Colander or clean kitchen towel to squeeze moisture from zucchini

Tips & Tricks

Salt the zucchini slices lightly and let them sit 10 to 15 minutes, then pat dry to reduce excess moisture and avoid a watery casserole.
Squeeze the chopped spinach very well after wilting or thawing so the custard sets nicely.
Shred your own mozzarella and Parmesan so they melt smoothly and avoid clumping.
Use feta in brine when possible since it tastes creamier and less chalky than dry blocks.
Taste the veggie mixture before adding eggs and adjust salt and herbs so the final dish tastes seasoned all the way through.
Add a little lemon zest to brighten flavors if your feta tastes very salty.
Grease the baking dish well and sprinkle a thin layer of breadcrumbs on the bottom for a subtle crust.
Let the casserole rest 10 minutes after baking so slices hold together and cut cleanly.
Double the recipe in two dishes if you plan to feed a crowd since leftovers vanish quickly.

How to Make Baked Zucchini Spinach and Feta Casserole Recipe

Step 1: Prep and sweat the zucchini

Slice the zucchini into thin half moons, about ⅛ to ¼ inch thick. Place the slices in a colander, sprinkle with a generous pinch of salt, and toss. Let them sit over the sink for 10 to 15 minutes so they release some water, then pat dry with paper towels.

Step 2: Sauté veggies and aromatics

Heat olive oil in a large skillet over medium heat. Add the diced onion and cook until it turns soft and lightly golden, about 6 to 8 minutes, stirring often. Stir in the garlic and cook 1 minute until it smells fragrant and toasty.

Add the zucchini slices to the skillet and cook 5 to 7 minutes, stirring occasionally, until they turn tender and lightly browned in spots. Season with a pinch of salt and pepper, then add the chopped spinach and cook 2 to 3 minutes until it wilts. Turn off the heat and let the veggie mixture cool slightly.

Step 3: Mix the custard base

In a large mixing bowl, whisk the eggs until smooth. Add milk, Greek yogurt or sour cream, oregano, basil, crushed red pepper flakes, and a pinch of salt and pepper. Whisk until the mixture looks creamy and well combined.

Sprinkle in the flour and whisk again until no dry pockets remain. Stir in the feta, mozzarella, and half of the Parmesan. If you use lemon zest, add it now and stir.

Step 4: Combine veggies with the egg and cheese mixture

Add the slightly cooled zucchini and spinach mixture to the bowl with the custard. Stir gently until the vegetables coat evenly with the egg and cheese mixture. Taste a small piece of zucchini and adjust salt or pepper if needed.

Grease your baking dish with a little olive oil. Sprinkle a tablespoon or two of breadcrumbs across the bottom of the dish to help form a light crust.

Step 5: Assemble the casserole

Pour the mixture into the prepared baking dish and spread it into an even layer. Sprinkle the remaining Parmesan and the rest of the breadcrumbs over the top. Drizzle a tiny bit of olive oil across the surface so the top browns nicely.

If you use green onions, scatter them over the top now or save them for garnish after baking. Place the dish on a baking sheet if you worry about any bubbling over.

Step 6: Bake until golden and set

Preheat your oven to 375°F while you assemble the casserole if you have not done that yet. Bake the casserole for 30 to 35 minutes until the top turns golden and the center feels set when you gently shake the dish. A knife inserted in the center should come out mostly clean with melted cheese, not liquid egg.

Let the casserole rest on a cooling rack for 10 minutes. Sprinkle with fresh parsley or dill before serving if you like a fresh herbal note.

What to Serve with Baked Zucchini Spinach and Feta Casserole Recipe

This Baked Zucchini Spinach and Feta Casserole Recipe pairs nicely with a crisp green salad with cucumbers, tomatoes, and a simple lemon olive oil dressing. You can add a side of roasted potatoes, quinoa, or brown rice if you want a heartier meal. I also like it with sliced fresh tomatoes and a bowl of fruit salad for a brunch spread.

Serve it warm with iced tea, sparkling water with citrus slices, or a light herbal lemonade. The salty feta and tender veggies balance nicely with bright, refreshing drinks.

Storage Options

Store leftovers in an airtight container in the fridge for up to 4 days.
Let the casserole cool completely before covering so condensation does not make the top soggy.
Reheat individual slices in the microwave for 1 to 2 minutes or in a 350°F oven for 10 to 15 minutes until hot.
Freeze portions tightly wrapped in plastic and then foil or in freezer containers for up to 2 months.
Reheat from frozen in a 350°F oven, covered, for about 25 to 30 minutes, then uncover for the last 5 minutes to crisp the top.