1. Preheat your oven to 350°F (175°C).
2. Bring a large pot of water to a boil. Carefully remove the core from the cabbage and place the whole head in the boiling water. Boil for about 2 minutes, then peel off the softened leaves. Continue until you have about 12 leaves. Set aside.
3. In a large mixing bowl, combine the ground beef, cooked rice, chopped onion, minced garlic, salt, and pepper. Mix well.
4. Place about ¼ cup of the meat mixture in the center of each cabbage leaf. Fold in the sides and roll up tightly.
5. In a large baking dish, spread a thin layer of tomato sauce on the bottom. Place the cabbage rolls seam-side down in the dish.
6. In a bowl, combine the remaining tomato sauce, diced tomatoes, and beef broth. Pour over the cabbage rolls.
7. Cover the dish with aluminum foil and bake for 1.5 hours, or until the cabbage is tender and the meat is cooked through.
8. Let cool slightly before serving. Enjoy!