In a large skillet, heat a tablespoon of olive oil over medium heat. Add the chopped onion and minced garlic, and sauté until the onion becomes translucent, about 3-4 minutes.
Add the ground beef or lamb to the skillet. Cook until browned, breaking it apart with a spatula, about 5-7 minutes. Drain any excess fat.
Stir in the tomato paste, Worcestershire sauce, thyme, salt, and pepper, mixing well to combine.
Mix in the frozen mixed vegetables and continue cooking for another 3-4 minutes, until heated through. Remove from heat.
In a muffin tin, spoon the meat mixture into each cup, filling them about halfway.
Top the meat mixture with a generous dollop of mashed potatoes, smoothing them out with the back of a spoon.
Sprinkle shredded cheddar cheese on top of each mini pie.
Bake in the preheated oven for 20-25 minutes, or until the tops are golden brown and the cheese is bubbly.
Allow them to cool for a few minutes before using a spoon to carefully lift them out of the muffin tin.
Notes
Serve on a rustic wooden board, garnished with fresh herbs for added color.