Place wheat berries in a 4- to 5-quart slow cooker. In a medium bowl whisk together broth, the water, molasses, mustard, and salt; pour into slow cooker. Add the sliced red onions, beets, and apricots.
Cover and cook on high-heat setting about 3 hours or until wheat berries are tender but still chewy.
Meanwhile, in a medium bowl combine oats, milk, the finely chopped onion, the 1 tablespoon parsley, the Worcestershire sauce, pepper, and garlic; gently mix in ground beef. Using a teaspoon shape meat mixture into 24 small meatballs. Stir meatballs into mixture in cooker
Cover and cook for 2 hours more. Stir in vinegar.
If desired, top each serving with sour cream and sprinkle with additional parsley.