Preheat oven to 350 degrees F (175 degrees C).
Remove the core from the cabbage and carefully separate the leaves. Bring a large pot of water to a boil and add the cabbage leaves. Cook for 2-3 minutes, or until softened. Remove the leaves from the water and set aside to cool.
In a large mixing bowl, combine ground beef, cooked rice, onion, parsley, garlic, egg, salt, and pepper. Mix well.
Place about 2-3 tablespoons of the beef mixture onto each cabbage leaf. Roll the leaf up, tucking in the sides, to create a neat package.
In a large pot or Dutch oven, combine diced tomatoes, beef broth, brown sugar, and apple cider vinegar. Bring to a simmer.
Place the stuffed cabbage rolls into the pot and spoon some of the sauce over the top.
Cover the pot and bake in the preheated oven for 1 1/2 hours, or until the cabbage is tender and the meat is cooked through. Serve warm. Enjoy!
