Old-Fashioned Sausage Gravy

1 lb. pork sausage
3 T. flour
2 cups whole milk
1/4 tsp. salt
1/4 tsp. pepper

In a large skillet, cook sausage over medium heat until browned and crumbly.  Using a slotted spoon, remove sausage from pan, reserving drippings in skillet.  Add enough vegetable oil to skillet to equal 3 tablespoons drippings, if necessary.  Add flour to skillet, whisking until smooth.  Cook over medium-high heat, whisking constantly, for 3 minutes or until lightly browned.  Reduce heat to medium.  Gradually add milk, whisking constantly, until gravy is thickened.  Stir in sausage, salt and pepper.  Serve immediately over hot biscuits or mashed potatoes.