Step 1: Preheat the Oven

1. Preheat your oven to 375°F (190°C). Grease a 9×13-inch baking dish with cooking spray or butter.

Step 2: Cook the Sausage

1. In a large skillet over medium heat, cook the breakfast sausage until browned and fully cooked. Break it into small crumbles as it cooks. Once done, remove the sausage from the skillet and set it aside.

Step 3: Make the Sausage Gravy

1. In the same skillet, melt the butter over medium heat. Add the flour and whisk continuously for 1-2 minutes to create a roux. Gradually pour in the milk, whisking constantly to avoid lumps. Add garlic powder, onion powder, paprika, salt, and pepper. Cook until the gravy thickens (about 3-5 minutes). Stir in the cooked sausage and remove from heat.

Step 4: Layer the Casserole

1. Spread the sausage gravy evenly across the bottom of the prepared baking dish. Sprinkle half of the shredded cheddar and mozzarella cheese over the gravy. Arrange the frozen tater tots in a single layer on top.

Step 5: Prepare the Egg Mixture

1. In a mixing bowl, whisk together the eggs and milk. Season with a pinch of salt and pepper. Pour the egg mixture evenly over the tater tots.

Step 6: Add the Remaining Cheese

1. Sprinkle the remaining shredded cheese over the top of the casserole.

Step 7: Bake the Casserole

1. Bake in the preheated oven for 40-45 minutes, or until the tater tots are golden brown and the eggs are fully set. If the top starts to brown too quickly, cover the dish with aluminum foil.

Step 8: Let It Rest

1. Remove the casserole from the oven and let it rest for 5-10 minutes before serving.