Preheat oven to 325F.
Lightly coat a 9x13" casserole with Pam. Spread the cabbage on the bottom.
Lightly coat a large pot with Pam and add the chopped onions, cooking over medium-high heat until soft and translucent. Add the meat and cook until no longer pink. Drain off any fat.
Add the tomato soup, tomato paste, sugar, vinegar, and rice, and simmer for 5 minutes.
Pour sauce over the cabbage and spread to even but do not mix.
Cover tightly with foil and bake at 325F for 1.5 hours. Let sit 5 minutes before serving.