Add the sausage to a large skillet set over medium heat. Once the pan is hot, add the sausage and cook, breaking it apart with a spatula, until it is cooked through, 5 to 7 minutes.
Sprinkle the flour atop the sausage and stir to combine. Cook, stirring, for 2 minutes.
While stirring, slowly stream in the milk. Bring the gravy to a boil then reduce it to a simmer and cook, stirring occasionally, until it thickens enough to coat the back of a spoon.
Taste and season the gravy with salt and black pepper.
Spoon the sausage gravy over halved biscuits and serve.