Preheat your oven to 180°C (350°F) and lightly grease a baking dish to prevent sticking and ensure easy removal after baking.

Heat a skillet over medium heat and add the crumbled chicken or turkey sausage, cooking it until fully browned and cooked through while breaking it into small pieces.

Once the sausage is cooked, drain any excess liquid or fat and set it aside to cool slightly.

In a large mixing bowl, crack the eggs and add the egg whites, then whisk thoroughly until fully combined and slightly frothy.

Add shredded mozzarella cheese and cottage cheese (or Greek yogurt) to the egg mixture, stirring until evenly incorporated.

Season the mixture with garlic powder, salt, and black pepper, mixing well to distribute the flavors evenly.

Add the cooked sausage and chopped spinach into the bowl, gently folding everything together to create a balanced mixture.

Pour the mixture into the prepared baking dish and spread it evenly using a spatula to ensure consistent thickness.

Place the dish into the preheated oven and bake for 30–35 minutes, or until the center is set and the top is lightly golden.

Remove from the oven and allow the casserole to rest for 5–10 minutes before slicing, helping it hold its shape and improving texture.

Cut into portions and serve warm for the best flavor and consistency.