GravyPotatoesBeefPeasLeftover Beef and Potato Casserole Diana Updated on March 17, 2024March 17, 2024 Leave a Comment on Leftover Beef and Potato Casserole1 min read Give your leftover roast beef a delicious makeover with this hearty casserole. Made with mashed potatoes, gravy, steamed peas, and cheddar cheese, it’s a meal you won’t want to miss.