The main ingredient in a traditional British shepherd's pie is minced lamb. This savory dish typically consists of cooked minced lamb mixed with vegetables like carrots and peas, all topped with creamy mashed potatoes. The dish is baked until the potato topping is golden brown, creating a comforting and hearty meal. When made with beef, it is referred to as "cottage pie." Shepherd's pie has become a staple in British cuisine, often enjoyed in homes and pubs alike for its delicious flavors and warming qualities.