Preheat the oven to 400°F (200°C).
Boil the sweet potatoes in a large pot of water for about 15 minutes or until tender. Drain and mash until smooth.
In a skillet, heat olive oil over medium heat. Add onion and garlic, cooking until soft.
Add the ground meat to the skillet and cook, breaking it up, until browned and it reaches 160°F (71°C). Stir in the mixed vegetables, tomato paste, thyme, salt, and pepper.
Transfer the meat and vegetable mixture to a baking dish. Spread the mashed sweet potatoes on top.
Bake in the preheated oven for 20-25 minutes or until the topping is slightly golden.
Serve warm, allowing everyone to enjoy the hearty flavors of this comforting dish.