Preheat your oven to 400°F (200°C).
In a skillet, heat the olive oil over medium heat. Add the diced onion and cook until translucent.
Add the minced garlic and cook for another minute.
Add the ground beef and cook until browned. Drain any excess fat.
Stir in the tomato paste, beef broth, frozen peas and carrots, salt, and pepper. Let it simmer for about 5 minutes.
Transfer the meat mixture to a baking dish and spread it out evenly.
Spread the mashed potatoes evenly over the meat mixture.
Bake in the preheated oven for about 20 minutes, or until the top is golden brown.
Let it cool for a few minutes before serving.