Shepherd's Pie Grandee

1. Preheat oven to 180°C (350°F). 2. Peel and boil potatoes until tender. Mash with milk, butter, salt, and pepper. 3. Heat oil in a large pan. Brown the minced lamb, then drain excess fat. Add chopped onion and carrots, and cook until softened. 4. Stir in tomato puree, Worcestershire sauce, and beef stock. Bring to a simmer and add peas. Cook for 10-15 minutes until the sauce has thickened. 5. Transfer the lamb mixture to an ovenproof dish. Top evenly with the mashed potatoes, using a fork to create peaks. 6. Bake for 25-30 minutes, or until the topping is golden and the filling is bubbling.