Preheat oven to 350°F and grease a 9x13 inch baking dish with cooking spray or butter.
In a large bowl, whisk together eggs, cottage cheese, garlic powder, onion powder, salt, and pepper until well combined.
Stir in shredded cheddar cheese, chopped spinach, diced tomatoes, and green onions until evenly distributed.
Pour mixture into prepared baking dish and spread evenly.
Bake for 30-35 minutes until the center is set and the edges are lightly golden.
Remove from oven and let cool for 5 minutes before slicing into squares.
Serve warm, or refrigerate for up to 4 days and reheat individual portions in the microwave.