Chop one medium onion and three cloves of garlic. Slice half a head of cabbage into thin strips to yield about 6 cups. Rinse 1 cup of rice under cold water.

In a large mixing bowl, combine ground beef, the diced onion, minced garlic, rinsed rice, and spices. Mix until evenly distributed.

Layer half of the sliced cabbage at the bottom of the slow cooker. Spread the beef mixture over it and top with remaining cabbage. Pour tomato sauce over everything.

Cover and cook on low for 6 to 8 hours until cabbage is tender.

Check doneness; fluff the mixture gently with a fork before serving.