1 1/2cups grated Colby cheese 1 cup is for the casserole topping
Preheat oven to 350 degrees.
Brown sausage in a large skillet over medium heat, be sure to break the sausage into small bite-sized pieces when browning. When sausage is almost done add 2 to 3 tablespoons of chopped red bell pepper into the sausage. Drain sausage when finished cooking.
Add 2 tablespoons of butter in a medium-sized saucepan. Add 2 tablespoons of flour to the butter. Allow the butter and flour to cook over medium heat for about 1 minute. You must cook the flour and butter mixture together so that the flour won't taste raw. Add 1/4 of the milk to the roux, and stir until thickened. Once the sauce is thick add another 1/4 of the milk, and stir until thickened. Finally add the remaining milk to the sauce once it has thickened.
Once the sauce has gotten thick add the cheese and stir until the cheese has melted. In a large bowl combine hash browns, cheese sauce, and sausage. Stir to combine. Pour mixture into a 13 x 9-inch baking dish. Top with additional grated Colby cheese.