Crockpot Beef Pepperoncini Recipe Type: Entree Serves: 12 Ingredients 1 (4 pound) beef rump roast ½ tsp garlic powder ½ tsp black pepper 1 (16 ounce) jar pepperoncini peppers, not drained Instructions Season roast with garlic powder and black pepper; place in slow cooker. Pour jar of peppers (with liquid) on top of roast.