Cook the bacon on a parchment-lined baking sheet at 400°F for about 20 minutes or until crispy. Transfer to a paper towel-lined plate, chop, and reserve a small amount for garnish.
Melt the butter in a skillet over medium heat. Add the diced onion and bell pepper, season with a little salt and pepper, and cook until softened. Remove and set aside.
In the same skillet, cook the breakfast sausage until browned. Reserve about ¼ cup of the sausage for garnish.
Add the bacon grease to the skillet with the remaining sausage. Stir in the flour and cook for 2 to 3 minutes. Slowly whisk in the half-and-half. Season generously with salt, pepper, and red pepper flakes. Simmer until thickened.
In a bowl, whisk together the eggs, milk, and Slap Ya Mama seasoning.
Grease a 9x13 baking dish. Add the hash browns and season with garlic powder, onion powder, black pepper, and additional Slap Ya Mama seasoning if desired.
Add most of the chopped bacon, the cooked peppers and onions, 1 cup sharp cheddar, 1 cup pepper jack, and 1 cup of the sausage gravy. Stir until well combined.
Pour the egg mixture evenly over the hash brown mixture.
Spread the remaining sausage gravy over the top and sprinkle with the remaining cheddar and pepper jack cheese.
Bake at 350°F for 45 minutes or until the eggs are set and the cheese is melted and lightly golden.
Garnish with the reserved sausage, reserved bacon, and sliced green onions.
Let rest for 10 minutes before slicing and serving.