Preheat the oven to 350 degrees F.

Spray a deep 13 by 9-inch casserole dish with vegetable oil cooking spray.

Melt the butter in a large frying pan. Add sausage and sauté until cooked through. Remove with a slotted spoon and place in a bowl and set aside. Add the onion and sauté over medium high and sauté for 4 minutes. Add red pepper and thyme and sauté for 4 minutes or until the onions are lightly browned. Add the hash browns and break apart and sprinkle with salt and pepper. Sauté about 5-10 minutes or until lightly browned. Set aside.

In a large mixing bowl, combine the milk, eggs, salt, pepper, and mustard, and whisk to blend. Stir in 1 cup cheddar, 1 cup Parmesan cheese. Set aside.

In a small bowl mix the remaining cheese together and set aside.

To assemble, spread the onions and hash browns evenly at the bottom of the greased dish. Evenly distribute the sausage over the hash browns. Place the bread cubes evenly on top of sausage. Pour the milk and egg mixture over these layers. Add the remaining cheese over the top of the casserole. Place foil over top of casserole and bake for 30 minutes.

Remove foil and continue baking for another 20-30 minutes or until the egg mixture has set and the casserole is puffy and the cheese has lightly browned. If the cheese is getting too brown, place foil back on casserole and continue cooking until cooked through and puffed and golden brown.