Leftovers Pot Pie Ingredients leftover roast beef leftover vegetables (peas, corn, green beans, etc.) leftover baked or boiled potatoes diced onion 1 package brown gravy mix salt and pepper to taste leftover biscuits Directions Cut up beef and put in crockpot with vegetables, potatoes, onion, gravy mix, salt, and pepper. Cook on low for 2 hours, then put leftover biscuits on top and continue to cook until biscuits are heated.