Prep Oven & Dish: Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish.
Layer the Cabbage: Spread the 1 shredded small cabbage in an even layer across the bottom of the prepared baking dish.
Cook the Beef Mixture: In a skillet, brown the 1 ½ lbs ground beef or turkey with the 1 chopped large onion and ½ cup chopped red bell pepper. Drain off any excess grease. Stir in the 1 (15 oz) can of diced tomatoes, ½ teaspoon salt, ¼ teaspoon pepper, ¼ teaspoon sugar, and the optional 1 teaspoon caraway seeds.
Assemble the Casserole: Spoon the cooked beef mixture evenly over the layer of cabbage in the baking dish. In a separate bowl, mix together the 1 (8 oz) can of tomato sauce and 1 cup reduced-fat sour cream. Spread this sauce mixture evenly over the beef layer.
Bake & Finish: Cover the baking dish with foil and bake for 1 hour. Uncover the dish, sprinkle the 1 cup shredded Swiss cheese over the top, and bake for an additional 15–20 minutes, or until the cheese is melted and bubbly.
Serve: Let the casserole rest for 10 minutes before serving.
Enjoy this comforting and easy-to-make casserole!