Crustless Cheesy Spinach Casserole

Prep Time: 15 minutes Cook Time: 35–40 minutes Total Time: 50–55 minutes Servings: 6 Cooking Method: Oven-Baked

Ingredients

10 oz (280g) fresh baby spinach, roughly chopped (or frozen spinach, thawed and squeezed dry)
1 tablespoon olive oil
1 medium yellow onion, finely diced
2 garlic cloves, minced
5 large eggs
½ cup plain Greek yogurt or sour cream
¼ cup whole milk or heavy cream
1½ cups shredded mozzarella cheese, divided
¾ cup crumbled feta cheese or ricotta cheese
½ cup freshly grated Parmesan cheese
¼ teaspoon ground nutmeg
½ teaspoon salt
¼ teaspoon freshly ground black pepper
Cooking spray or a little olive oil for greasing

Instructions

Step 1: Preheat the Oven

Preheat your oven to 375°F (190°C). Lightly grease an 8×8-inch or 9×9-inch baking dish with olive oil or cooking spray. Make sure the bottom and sides are evenly coated to prevent sticking.

Step 2: Sauté the Onion and Garlic

Heat 1 tablespoon of olive oil in a large skillet over medium heat. Add the finely chopped onion and cook for 3–4 minutes, stirring occasionally, until softened and slightly translucent.

Add the minced garlic and cook for another 30 seconds, stirring continuously until fragrant. Avoid browning the garlic, as it may develop a bitter taste.

Step 3: Cook the Spinach

Add the chopped fresh spinach to the skillet in batches, stirring gently as it wilts. Continue cooking for approximately 2–3 minutes until all the spinach has softened and reduced in volume.

Remove the skillet from the heat and allow the mixture to cool slightly. If there is excess liquid, gently squeeze or drain the spinach to prevent the casserole from becoming watery.

If using frozen spinach, thaw it completely, squeeze out as much moisture as possible, and stir it into the cooked onion and garlic mixture.

Step 4: Prepare the Creamy Egg Mixture

In a large mixing bowl, crack the 5 eggs and whisk until the yolks and whites are fully combined.

Add the Greek yogurt or sour cream, milk or heavy cream, salt, black pepper, and ground nutmeg.

Whisk thoroughly until the mixture becomes smooth and creamy. This mixture will help create a soft, fluffy, and rich casserole texture.

Step 5: Mix in the Cheeses

Add 1 cup of shredded mozzarella, the crumbled feta or ricotta, and the grated Parmesan cheese to the egg mixture.

Using a spatula, gently fold everything together until the cheese is evenly distributed.

The mozzarella provides a delicious stretchy texture, while feta adds a slightly tangy flavor. Parmesan brings a rich, savory taste that complements the spinach.

Step 6: Combine the Spinach and Egg Mixture

Add the cooked spinach, onion, and garlic mixture to the bowl containing the eggs and cheese.

Gently stir until all the ingredients are evenly combined. Make sure the spinach is distributed throughout the mixture so every serving contains a balanced amount of vegetables and cheese.

Pour the prepared mixture into the greased baking dish. Use a spatula to spread it evenly and smooth the surface.

Step 7: Add the Mozzarella Topping

Sprinkle the remaining ½ cup of shredded mozzarella evenly across the top of the casserole.

This final layer of cheese will melt during baking and create a beautifully golden, bubbly, and slightly crispy topping.

Step 8: Bake Until Golden and Set

Place the baking dish on the middle rack of the preheated oven.

Bake for approximately 32–35 minutes, or until the edges are lightly golden and the center appears firm and no longer jiggles when the dish is gently shaken.

For a deeper golden-brown cheese topping, switch the oven to broil for an additional 2–3 minutes. Watch carefully during broiling to prevent the cheese from burning.

The casserole is fully cooked when the center reaches 160°F (71°C).

Step 9: Allow the Casserole to Rest

Carefully remove the baking dish from the oven and place it on a heat-resistant surface.

Allow the casserole to rest for 8–10 minutes before slicing. This resting time helps the egg and cheese mixture firm up, making it easier to cut into clean, even portions.

Step 10: Slice and Serve

Using a sharp knife, cut the casserole into 6 generous portions.

Serve warm while the mozzarella is still soft and melty. Pair it with toasted bread, a fresh green salad, roasted vegetables, or your favorite breakfast sides.

Enjoy your homemade Crustless Cheesy Spinach Casserole, filled with tender spinach, creamy eggs, and three delicious cheeses!