Preheat the oven to 350°F (175°C).

Grease an oven-safe casserole dish with cooking spray or butter.

In a saucepan over medium heat, add a drizzle of oil and sauté the chopped onion and minced garlic until fragrant, about 2–3 minutes.

In a mixing bowl, combine the chopped spinach, cottage cheese, beaten eggs, shredded mozzarella, grated Parmesan, sautéed onion and garlic, breadcrumbs, salt, pepper, and paprika. Mix until evenly coated.

Transfer the mixture into the prepared casserole dish and press down gently to level.

If desired, sprinkle additional mozzarella or breadcrumbs on top for a crispy layer.

Bake the casserole in the preheated oven for 30 minutes, or until the top is golden brown and set.

Remove from the oven and let cool for 5 minutes before slicing and serving.