To make the sausage gravy:
In a large skillet, cook the sausage over medium heat until it is browned and crumbled.
Remove the sausage from the skillet with a slotted spoon and set it aside.
In the same skillet, melt the butter over medium heat.
Add the flour, salt, and pepper to the skillet and whisk to combine.
Slowly add the milk to the skillet, whisking constantly, until the mixture is smooth and thickened.
Add the cooked sausage back to the skillet and stir to combine.