In a large, deep skillet, cook the sausage, stirring to break up the pieces, until browned and no longer pink, 5 to 6 minutes. Using a slotted spoon, remove the sausage to paper towels to drain.
Carefully remove all but 2 tablespoons of grease from the pan and return to medium-high heat. Add the onions, garlic, and pepper and cook, stirring, until soft, about 2 minutes. Add the flour and cook, stirring, for 1 minute. Add the milk and bring to a boil. Reduce the heat and cook, stirring, until thickened, 4 to 5 minutes. Add the cooked sausage into the gravy, stir well, and cook to heat through, 30 to 45 seconds. Serve hot.
Makes 4 servings