Preheat the oven to 375°F (190°C). Spray a 9×13 inch baking dish with cooking spray to prevent sticking.

Spread the diced red bell pepper, yellow onion, and chopped spinach evenly across the bottom of the prepared baking dish.

In a large mixing bowl, crack the 12 eggs and whisk thoroughly. Add the full-fat cottage cheese, garlic powder, Italian seasoning, kosher salt, ground black pepper, and ¼ cup of the shredded gruyere or gouda cheese. Stir well until combined.

Pour the egg and cottage cheese mixture evenly over the vegetable layer in the baking dish.

Sprinkle the remaining ½ cup of shredded cheddar cheese evenly over the top of the egg mixture.

Place the baking dish on the middle rack of the preheated oven. Bake for approximately 50 to 55 minutes, or until the egg bake is set and a knife inserted in the center comes out mostly clean.

Remove from the oven and allow to cool for at least 15 minutes. Slice into portions and serve warm.