Leftover roast beef hash is a hearty and flavorful dish that transforms leftover roast beef into a delicious breakfast or brunch option. The roast beef is diced and combined with potatoes, onions, and seasonings, then cooked until crispy and golden. This hash can be served on its own or topped with a fried egg for added richness. It's a great way to repurpose leftovers and create a satisfying meal.