Nothing is better than a hearty homemade soup, but sometimes hours of simmering and stirring doesn't fit into your schedule. Skip the hours of work with this simple meatball soup recipe. With help from frozen, pre-made meatballs and your slow cooker, having homemade soup is as easy as adding all of the ingredients to the pot and going about your day. For extra flavor and nutrients, feel free to add some diced carrots and celery to the soup along with the chopped onions. Carrots are a good way to add subtle natural sweetness to a dish, and picky eaters aren't likely to notice them if the dice is quite small. For the frozen mixed vegetables, choose a corn and green bean medley or one with lima beans. Or add a handful of fresh chopped spinach, chard, or kale to give the soup a flavor and color boost. For faster cooking vegetables, like frozen peas or green beans, cut the final cooking down by half. The soup is excellent with garlic bread or a crusty loaf of french bread. Add a tossed green salad or caesar salad for a satisfying dinner.