Boil the chopped potatoes in a large pot of salted water for 10–12 minutes until fork-tender. Drain and return to the pot. Add milk, butter, salt, and pepper, then mash until creamy and smooth. Set aside.

In a large skillet over medium heat, brown the ground meat until fully cooked, about 5–7 minutes. Drain any excess fat, then add chopped onion and minced garlic, sautéing until translucent, about 3–4 minutes.

Add frozen peas, carrots, tomato paste, beef broth, and Worcestershire sauce to the skillet with the meat. Stir and let it simmer for 3–5 minutes until thickened.

Preheat your oven to 400°F (200°C). Grease a muffin tin. Spoon meat filling into each muffin cup until two-thirds full, then top with mashed potatoes. Optionally, sprinkle cheddar cheese on top.

Bake for 10–15 minutes or until the tops are golden brown. Broil for an additional 2–3 minutes for a crispy top.

Remove from the oven and let cool slightly. Garnish with parsley and serve warm.