For the sausage gravy: Place heavy-duty skillet over medium heat. Break up sausage in skillet and cook the sausage completely. To make the gravy, sprinkle half the flour over the sausage and stir until flour disappears. Add the remaining flour and stir for another minute, then pour in the milk. Stir constantly until smooth. Cook over low heat and simmer gently for 10 minutes. Taste and adjust seasoning with salt and pepper. Spoon the gravy over warm biscuits and serve.