Heat a large skillet over medium-high heat. Add ground meat and cook until browned, about 5-7 minutes, breaking it apart with a spatula. Transfer cooked meat to a plate.
1 lb ground beef or lamb
In the same skillet, add chopped onion and minced garlic. Sauté until onion becomes translucent and fragrant, about 3-4 minutes. Return the cooked meat to the skillet.
1 lb ground beef or lamb
Add tomato paste and frozen peas to the skillet. Stir well and cook for 2 minutes until tomato paste darkens slightly.
1 lb ground beef or lamb
Pour in broth and bring to a simmer. Reduce heat to low and cook uncovered for 10 minutes, letting the mixture thicken and flavors meld.
1 lb ground beef or lamb
Meanwhile, place peeled and cubed potatoes into a saucepan. Cover with cold water and bring to a boil over high heat. Cook until potatoes are tender when pierced with a fork, about 15 minutes.
1 lb ground beef or lamb
Drain the potatoes and return them to the hot pan. Add butter and warm milk. Mash until smooth and creamy, then season with salt and pepper to taste.
1 lb ground beef or lamb
Preheat oven to 400°F (200°C). Spread the meat filling in a baking dish evenly. Top with the mashed potatoes, spreading smoothly and creating a slightly ruffled surface for a crispy edge.
1 lb ground beef or lamb
Bake in the preheated oven for 20-25 minutes, until the top is golden brown and crispy. Let rest for a few minutes before serving.
