The primary ingredient in a shepherd's pie is ground meat, traditionally lamb. This classic dish, originating from the UK, consists of a savory meat filling that is typically cooked with vegetables like carrots, peas, and onions. The dish is topped with a creamy layer of mashed potatoes before being baked until golden brown. In some regions, shepherd's pie may use ground beef instead and is often referred to as cottage pie. The combination of hearty meat and fluffy potatoes creates a comforting meal that has stood the test of time, making it a popular choice for many families.