Name: Baked Zucchini Spinach and Feta Casserole Recipe
Prep time: 20 min
Cook time: 30 min
Total time: 50 min
Ingredients: 3 medium zucchini, thinly sliced into half moons; 3 cups fresh spinach, packed and roughly chopped; 1 small yellow onion, finely diced; 3 cloves garlic, minced; 2 tablespoons fresh dill, chopped; 2 tablespoons fresh parsley, chopped; 1 cup feta cheese, crumbled; 1 cup shredded mozzarella or low moisture provolone; 1 cup whole milk or half and half; 3 large eggs; 1 cup panko breadcrumbs; 2 tablespoons grated Parmesan cheese; 2 tablespoons olive oil, plus extra for greasing the dish; 1 teaspoon kosher salt; 1/2 teaspoon black pepper; 1/2 teaspoon dried oregano; 1/4 teaspoon red pepper flakes; 1/2 cup cooked quinoa or rice; 1/4 cup sun dried tomatoes, chopped; 1 lemon, zested

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 brunches and takes about 50 minutes from start to finish. I first made this on a hot summer night when my neighbor dropped off a mountain of zucchini, and it has stayed in my regular rotation ever since.

Why Baked Zucchini Spinach and Feta Casserole Recipe Is Worth It

This casserole packs in a lot of vegetables while still tasting rich and cozy, so picky eaters usually clean their plates without a speech about nutrition. Zucchini, spinach, and feta balance each other, so the dish tastes bright and savory instead of heavy.

You mix everything in one bowl, then bake it in one pan, so cleanup stays easy. It works as a main dish or a side, and you can serve it warm, room temperature, or cold from the fridge.

“This Baked Zucchini Spinach and Feta Casserole Recipe tastes like spanakopita met a crustless quiche and decided to become my new favorite weeknight dinner. ★★★★★”

Ingredients You Need

Fresh produce

3 medium zucchini, thinly sliced into half moons
3 packed cups fresh spinach, roughly chopped
1 small yellow onion, finely diced
3 cloves garlic, minced
2 tablespoons fresh dill, chopped (or 2 teaspoons dried dill)
2 tablespoons fresh parsley, chopped

Dairy and eggs

1 cup crumbled feta cheese
- Use a block of feta in brine if possible, since it tastes creamier and saltier than pre-crumbled.
1 cup shredded mozzarella or low moisture provolone
- Pre-shredded works fine here and saves time.
1 cup whole milk or half and half
3 large eggs

Dry ingredients and pantry staples

1 cup panko breadcrumbs
- Use regular or whole wheat; gluten free panko works too.
2 tablespoons grated Parmesan cheese
2 tablespoons olive oil, plus extra for greasing the dish
1 teaspoon kosher salt, plus more to taste
½ teaspoon black pepper
½ teaspoon dried oregano
¼ teaspoon red pepper flakes (optional, for a little heat)

Optional add ins

½ cup cooked quinoa or rice for a heartier casserole
¼ cup sun dried tomatoes, chopped, for extra tang
Zest of 1 lemon for a brighter flavor

Equipment list

9×13 inch baking dish or similar casserole dish
Large mixing bowl
Cutting board and sharp knife
Measuring cups and spoons
Whisk
Large skillet (optional but helpful if you want to sauté the onion and garlic first)
Aluminum foil

Quick Tips & substitutions

Slice zucchini evenly so it bakes at the same rate and stays tender, not mushy.
Pat zucchini slices dry with a paper towel if they look very wet, since that helps avoid a watery casserole.
Use frozen spinach if you want; thaw it fully and squeeze out as much water as possible.
Swap mozzarella with cheddar, Monterey Jack, or a pizza blend if that is what you have.
Choose lactose free milk and cheese if you need a gentler option for dairy sensitive eaters.
Use gluten free panko or crushed gluten free crackers to keep the casserole gluten free.
Add cooked chicken, turkey, or chickpeas to turn this into a full protein packed main dish.
Taste the feta first and adjust the salt, since some brands taste much saltier than others.
Grease the baking dish well so the cheesy edges release easily and stay crispy.
Let the casserole rest 10 minutes after baking so it slices cleanly and holds its shape.

How to Make Baked Zucchini Spinach and Feta Casserole Recipe

Step 1: Prep the oven and pan

Preheat your oven to 375°F. Lightly grease a 9×13 inch baking dish with olive oil and set it aside. This step keeps the casserole from sticking and helps the edges crisp.

Step 2: Prep the vegetables

Wash the zucchini and trim the ends, then slice into thin half moons about ⅛ to ¼ inch thick. Chop the spinach into bite sized pieces so it folds into the mixture easily. Dice the onion and mince the garlic.

Step 3: Optional sauté for extra flavor

Heat 1 tablespoon olive oil in a skillet over medium heat. Add the onion and cook 3 to 4 minutes until it softens and turns lightly golden. Stir in the garlic and cook 30 seconds until fragrant, then remove from heat and let it cool slightly.

Step 4: Mix the egg and dairy base

In a large mixing bowl, whisk the eggs until smooth. Add the milk or half and half, salt, pepper, oregano, and red pepper flakes, then whisk again until everything blends. Stir in the dill, parsley, and lemon zest if you use it.

Step 5: Add cheeses and vegetables

Stir the crumbled feta and shredded mozzarella into the egg mixture. Add the sliced zucchini, chopped spinach, and the sautéed onion and garlic. Toss everything gently until the vegetables coat evenly in the cheesy mixture.

Step 6: Assemble the casserole

Pour the mixture into the greased baking dish and spread it into an even layer. In a small bowl, mix the panko, Parmesan, and 1 tablespoon olive oil until the crumbs look lightly coated. Sprinkle this mixture evenly over the top of the casserole.

Step 7: Bake to golden perfection

Cover the dish loosely with foil and place it in the oven. Bake for 20 minutes, then remove the foil so the top can brown. Continue baking 15 to 20 more minutes, until the center sets and the top turns golden and crisp.

Step 8: Rest and serve

Take the casserole out of the oven and let it rest for about 10 minutes. This short rest helps the cheese firm up slightly so slices hold together. Cut into squares and serve warm, or let it cool to room temperature for easier packing in lunch containers.

Recipe Variations

Gluten free: Use gluten free panko or crushed gluten free crackers in place of regular breadcrumbs.
Low carb: Skip the panko topping and sprinkle extra mozzarella and Parmesan on top instead.
Vegan: Use a plant based milk, vegan feta style cheese, and a vegan mozzarella style shred, and replace eggs with a chickpea flour batter or a liquid egg substitute that suits baking.
Extra protein: Stir in 1 to 2 cups cooked chicken, turkey, ground turkey, or chickpeas.
Extra veggies: Add chopped bell peppers, mushrooms, or grated carrot to the mix.
Spicier version: Increase red pepper flakes or add a small diced jalapeño.
Brighter flavor: Add more fresh herbs like basil or mint and extra lemon zest.

Ways to Serve Baked Zucchini Spinach and Feta Casserole Recipe

Serve warm with a simple green salad and crusty bread or garlic toast.
Pack chilled squares in lunch boxes with hummus and raw veggies.
Pair with roasted potatoes or sweet potatoes for a hearty vegetarian dinner.
Cut into small squares and serve as a brunch side with scrambled eggs.
Serve at room temperature with sliced tomatoes and cucumber on the side.

Storage Success

Let the casserole cool to room temperature, then cover the dish tightly or transfer slices to airtight containers. Store in the fridge for up to 4 days, and reheat individual portions in the microwave or in a 350°F oven until hot. Freeze cooled slices on a baking sheet, then move them to freezer bags and keep them up to 2 months. Reheat frozen pieces in the oven so the topping stays crisp and the texture stays pleasant.