Set the oven to 375°F and lightly spray a quiche pan or pie dish with cooking spray.
In a skillet, cook 1 lb of ground sausage over medium heat, crumbling it as it cooks. Once fully cooked, drain any excess grease.
Add 12 oz of diced frozen hashbrowns to the skillet with the ground sausage. Cook for 2-3 minutes, or until heated through. If needed, add a little oil to prevent sticking. Once cooked, remove from heat. Fold a paper towel and swish around using a spatula to absorb any excess grease.
In a large bowl, beat 10 large eggs until well combined.
Stir in the cooked sausage and hashbrowns to the eggs. Sprinkle in 1 tablespoon taco seasoning, ¼ cup shredded Mexican cheese, and ½ cup chopped tomato. Mix everything together.
Pour the egg mixture into your prepared quiche or pie dish. Use a fork to arrange the ingredients in a nice presentation by gently dragging them through the mixture. Lastly, sprinkle the ¼ cup cheese over top.
Place the dish in the oven and bake for 22-26 minutes, or until the eggs are fully set. (If needed, check the eggs at the 22-minute mark, but it may take up to 26 minutes.)
Remove from oven and let sit 10 minutes before slicing and serving.