Slow Cooker Italian Meatball Soup So easy and so delicious! I used no-salt tomatoes and low sodium broth. However, I felt the cook time of 8-10 hours was too long. Mine cooked just over eight, and my meatballs were falling apart. Next time I will start checking the meatballs at about 6-7 hours. I'd like them cooked but still firm. This is definitely a recipe that is going into my "regulars"!!!!