Prepare your biscuits according to your recipe or package directions. They should be warm and ready when the gravy is finished.
Add the sausage to a large skillet over medium heat. Break it into small crumbles with a wooden spoon as it cooks. Cook for 6-8 minutes until the sausage is no longer pink and is nicely browned.
Use a slotted spoon to transfer the cooked sausage to a plate lined with paper towels. Leave the drippings in the skillet. You should have about ¼ cup of drippings. If your sausage was lean and produced less fat, add enough butter to the skillet to equal ¼ cup total fat.
Whisk the flour into the hot drippings until smooth. Cook over medium heat for 1-2 minutes, whisking constantly, until the mixture smells toasted and turns a light golden color.
Slowly whisk in the warm milk, starting with about ½ cup and whisking until smooth before adding the rest. Once all the milk is added, cook for 3-5 minutes, whisking frequently, until the gravy is thick and bubbly. The gravy should coat the back of a spoon.
Stir the cooked sausage back into the gravy. Taste and season with salt and black pepper as needed (remember, the sausage is already seasoned, so you may not need much salt).
Split the warm biscuits in half and spoon the hot sausage gravy generously over the top. Serve immediately.
