1) Preheat over to 350 degrees
2) Combine Cheddar and mozzarella cheese in a small bowl; place 3 cups cheese mixture into a 9X13 pan
3) Add the sausage to a large skillet and place over medium heat. Break the sausage apart with a wooden spoon. Cook until the sausage is completely brown, about 7 minutes, stirring occasionally. Drain off the fat
4) Melt butter in a separate large skillet over medium heat; cook and stir mushrooms and red peppers until vegetables are tender, about 5 minutes, drain
5) Combine the frozen potatoes, cooked and drained sausage, and vegetables to a large bowl. Stir to combine.
6) Spread hashbrown, veggie, and sausage mixture over cheese.
7) Beat eggs in a bowl; mix in milk, flour, parsley, basil, salt, and pepper. Slowly pour egg mixture into baking dish.
8) Sprinkle 1 cup remaining cheese over the eggs
9) Bake in preheated oven until a knife inserted near the center comes out clean, 35 to 40 minutes.
10) Let stand 10 minutes before cutting.