Preheat oven to 325 degrees F (165 degrees C). Grease a 2 quart casserole dish.
Steam the whole head of cabbage until it is al dente. Meanwhile, in a saucepan bring 3 cups of water to a boil. Add rice and stir. Reduce heat, cover and simmer for 20 minutes.
Melt butter in a small skillet over medium heat. Saute onion until translucent; stir into cooked rice. Season with salt and pepper to taste.
Cut the leaves off of the cabbage and cut the larger leaves in half. Spoon 1 tablespoon of rice into a leaf and roll tightly. Place rolls in prepared casserole dish, stacking in layers. Pour tomato juice over the rolls, using enough just to cover.