Preheat your oven to 325°F (165°C).

In a large mixing bowl, combine the thawed spinach, cottage cheese, crumbled feta, grated Parmesan, chopped onion, garlic powder, black pepper, and nutmeg. Stir until evenly blended.

In a separate bowl, beat the eggs until well combined. Fold beaten eggs into the spinach mixture until just blended.

Lightly grease your baking dish and pour the spinach mixture into it, spreading it evenly.

Bake for approximately 45 minutes until the top is golden and edges are set.

Let the casserole cool for about 10 minutes before slicing to serve.