Melt butter in the same pan with reserved pork drippings. Once melted, add flour, salt and pepper. Mix well into melted butter and reserved drippings. Cook flour mixture for one minute, stirring the whole time.
Once the flour smell has gone, drizzle in milk, whisking mixture the entire time to break down the roux paste into the milk. Bring to a boil over medium to high heat and cook until desired thickness. This should only take 3 to 5 minutes.