Cook bacon in large skillet until crispy. Remove cooked bacon to paper towels to absorb grease. When cool, crumble bacon into small pieces. Set aside.
Do NOT clean skillet. Leave 2 Tablespoons bacon grease in skillet. Discard the rest.
In separate bowl or container, whisk together milk, flour, salt and pepper, until lump-free. Pour the milk/flour mixture into skillet with remaining bacon grease. Add crumbled bacon pieces. Heat mixture on medium (whisking/stirring constantly) until it comes to a boil; reduce heat a bit, and continue cooking and stirring, until gravy has thickened (5-6 minutes). Give it a taste test.
Add additional salt and pepper, to taste (I ALWAYS add more). Once gravy has thickened, add 1-2 Tablespoons cold butter. Stir until butter is melted, incorporated into gravy, and mixture is heated through.
Slice warm biscuits in half horizontally. Place biscuit halves onto serving plate. Spoon hot gravy over each half. Serve and enjoy!
