Finely chop the onion. Heat oil in a large frying pan over medium-high heat. Add the minced meat and fry for 5-8 minutes, breaking it up as it cooks, until browned. Add the chopped onion and fry for another 2-3 minutes until softened. Stir in the tomato paste and season with salt and pepper. Transfer to a baking dish.
In the same frying pan, combine the sauerkraut, vegetable or chicken broth, and a pinch of caraway seed. Simmer over medium heat for 30 minutes.
Preheat oven to 180°C (350°F). Spread the simmered sauerkraut mixture over the minced meat in the baking dish.
Mix the sour cream with salt and pepper to taste. Spread it evenly over the sauerkraut layer.
Bake for 30 minutes. The internal temperature should reach at least 74°C (165°F).
Dust with paprika powder. Serve with potato pancakes or mashed potatoes.