In a large skillet, cook pork sausage together with finely chopped onions on medium heat until the sausage is cooked through and is no longer pink. Add chopped red bell pepper, black beans, and diced green chili peppers. Add half the spices (1/2 teaspoon of chili powder and 1/2 teaspoon of cumin) and mix everything up.
Add shredded cheddar cheese, shredded mozzarella cheese, and hash browns to the sausage mixture and mix them in.
In a small bowl, whisk eggs, heavy cream, and the remaining half of spices (1/2 teaspoon of chili powder and 1/2 teaspoon of cumin).
Use 2.8 L (3 quarts) rectangular baking dish - 11 inches long x 8.5 inches wide x 3 inches deep. Brush the bottom and the sides of the baking pan with 1 tablespoon of melted butter.
Add half the sausage mixture to the baking pan, and pour half of the egg mixture over the sausage mixture, carefully and evenly. Add the remaining half of the sausage mixture on top, and pour the remaining half of the egg mixture evenly over the sausage mixture.
Bake, uncovered for about 40-50 minutes. The casserole is ready when the eggs are set and no longer liquid in the center. Let the dish cool for about 30 minutes before slicing it.