01 - Preheat oven to 400°F.
02 - Place potatoes in a large pot of salted boiling water. Cook for 15–20 minutes until tender. Drain thoroughly and mash with butter, milk, salt, and pepper. Stir in cheddar cheese if using. Set aside.
03 - Heat olive oil in a large skillet over medium heat. Add onion and carrot. Sauté for 4–5 minutes until softened.
04 - Stir in garlic and cook for 1 minute until fragrant.
05 - Add ground beef or lamb to the skillet. Break up with a spoon and cook until browned. Drain excess fat if necessary.
06 - Add tomato paste, Worcestershire sauce, thyme, salt, and pepper. Stir well to combine.
07 - Pour in broth and add peas. Simmer for 5 minutes until slightly thickened. Remove from heat.
08 - Divide meat filling evenly among six lightly greased ramekins or muffin tin wells.
09 - Spoon or pipe mashed potatoes over each filling, spreading to cover completely.
10 - Place ramekins on a baking sheet. Bake for 20 minutes until tops are golden and filling bubbles at edges.
11 - Let cool for 5 minutes before serving.