Preheat Oven: Preheat your oven to 375°F (190°C). Lightly grease a baking dish with olive oil or butter.
Prepare Veggies: In a pan, lightly sauté the diced onion and spinach over medium heat for 2-3 minutes, just until softened. Remove from heat and let it cool slightly.
Mix the Egg Mixture: In a large mixing bowl, whisk together the eggs, cottage cheese, shredded cheddar, garlic powder, salt, and pepper until well combined.
Add Veggies: Gently fold the sautéed spinach, onion, and diced tomato into the egg mixture.
Assemble: Pour the mixture evenly into the prepared baking dish. Use a spatula to spread it out evenly.
Bake: Bake in the preheated oven for 18-22 minutes, or until the eggs are set in the center and the edges are golden.
Rest & Serve: Remove from the oven and let it rest for 5 minutes before slicing. Garnish with fresh herbs or chili flakes, and serve warm.