Preparation Steps

• Preheat your oven to 400°F (200°C).
• Boil the potatoes in a large pot of salted water until tender, about 15-20 minutes. Drain well.
• Mash the potatoes with the warmed milk, butter, salt, and pepper until smooth and creamy. Set aside.
• In a large skillet or Dutch oven, brown the ground lamb over medium-high heat. Drain off any excess fat.
• Add the chopped onion, diced carrots, and diced celery to the skillet. Cook until softened, about 5-7 minutes.
• Stir in the minced garlic and cook for 1 minute more until fragrant.
• Sprinkle the flour over the meat and vegetable mixture and stir to coat. Cook for 1 minute.
• Gradually stir in the beef broth and Worcestershire sauce. Bring to a simmer, then reduce heat and cook for 10 minutes, stirring occasionally, until the sauce thickens.
• Stir in the dried thyme, salt, pepper, and frozen peas. Cook for 2 minutes.
• Pour the lamb filling into a 9x13 inch baking dish.
• Spread the mashed potatoes evenly over the lamb filling.
• Bake for 20-25 minutes, or until the potato topping is golden brown and the filling is bubbly.
• Let stand for 10 minutes before serving.