Slow Cooker Spaghetti and Meatballs Looking for the worlds easiest, fail proof dinner recipe?!?! You are going to love this recipe for Slow Cooker Spaghetti & Al Fresco Meatballs. Simply put all the ingredients in your Ninja 3-in-1 cooking system or favorite slow cooker and let it do the work for you! Other slow cooker recipes: Slow Cooker