Put the frozen meatballs in your slow cooker. 1 bag frozen meatballs Slice the onion and add it to the slow cooker. Pour in the French onion soup and sprinkle the soup mix over the top.

Place frozen meatballs in crockpot. Top with sliced onions and minced garlic. In a mixing bowl or large measuring cup, combine the beef broth, French onion soup, balsamic vinegar, thyme ...