Preheat the oven to 375°F.
Boil potatoes in salted water until tender, around 15 minutes. Drain and mash with milk, butter, salt, and pepper.
Brown beef in a skillet over medium heat, for 5 minutes.
Add onion, garlic, and carrots. Cook for 5 minutes until veggies soften.
Mix in peas, tomato paste, Worcestershire sauce, beef broth. Simmer for 5 minutes.
Sprinkle flour, and stir to thicken, 2-3 minutes.
Transfer mixture to baking dish. Spread mashed potatoes on top.
Bake for 30-35 minutes until lightly browned and bubbling.
Cool briefly before serving. Enjoy a hearty meal!