1. In a heavy bottom stock pot or skillet, whisk together bacon drippings and flour over medium heat. Continue to cook until the mixture browns slightly, about 5 minutes, but be careful not to let it burn.
2. Add milk, 1 cup at a time, whisking thoroughly with each addition. Continue to whisk over medium heat until gravy is smooth and begins to thicken. Add salt and pepper.
3. Serve over warm biscuits and top with chopped bacon pieces.