Add the frozen meatballs, onion, carrot, garlic, Italian seasoning, and chicken broth to your slow cooker.
Cook on high for 3-4 hours or low for 6-7 hours until the vegetables are tender and the meatballs are fully warmed through.
Stir in the acini de pepe pasta and chopped spinach. Cook for an additional 45 minutes on high, or until the pasta is tender and the spinach has wilted.
Allow the soup to cool slightly before serving to toddlers. Pair it with bread!