Preheat oven to 350°F. Grease a 9x13 baking dish.
Layer shredded cabbage in the bottom of the dish.
In a skillet, brown the beef with onion and bell pepper. Drain.
Stir in diced tomatoes, salt, pepper, sugar, and caraway seeds.
Spoon the beef mixture over the cabbage.
Mix tomato sauce and sour cream in a bowl, then spread over the beef layer.
Cover with foil and bake for 1 hour.
Uncover, sprinkle with cheese, and bake an additional 15–20 minutes.
Let rest 10 minutes before serving.