I got this recipe from a community cookbook years ago - they were trying to raise money to get their community center some new flooring. It was called unstuffed cabbage rolls in the book but we call it just "Cabbage Roll Casserole". Not exactly as good as real cabbage rolls but a really close second if you haven't the time or inclination to fuss with cabbage rolls.
In a large skillet, heat oil over medium heat. Add the ground meat and onion and cook, stirring, until ground beef is no longer pink and onion is tender. I don't use oil if I'm using beef because even the lean beef is usually fat enough without.
Add rice to meat mixture. Add the garlic and continue cooking for 1 minute. Add the chopped cabbage, tomatoes, tomato sauce, pepper, and salt. Bring to a boil. Cover and place in a slow (300 degree) oven for 2 to 3 hours. You can also pour into a slow cooker, cover and cook on low for 6-7 hours.