Preheat oven to 375°F (190°C). Grease a 9x13 baking dish with cooking spray.
Crumble the thawed cauliflower hashbrowns into the bottom of the baking dish, spreading them evenly.
In a large bowl, whisk together eggs, egg whites, and milk. Season with salt and pepper to taste.
Add the taco seasoning to the egg mixture and whisk well to combine.
Fold in the sauteed peppers with the egg mixture.
Pour the egg mixture over the cauliflower hashbrowns in the baking dish.
Bake for 30-35 minutes, or until the eggs are set and the center is no longer runny.
Remove from oven and let cool slightly before serving.
Garnish with your desired toppings (avocado, salsa, cilantro, sour cream) and enjoy!