Use a 6 quart slow cooker. Put the broth, vegetables, pasta sauce, and mint into your slow cooker. Stir in frozen meatballs. Cover and cook on low for 8-9 hours. The seasoning from the meatballs is what is going to flavor your soup. The longer and slower you cook the soup, the more flavor the broth will have. Stir in frozen peas 20 minutes or so before serving. Garnish with a bit of shredded Parmesan cheese.