Preheat oven to 400°F and line a rimmed baking sheet with parchment paper.
In a large mixing bowl, gently mix together the meatball ingredients until just combined.
Roll small 1 ¼ inch meatballs and place them onto the prepared baking sheet.
Bake meatballs for 16-18 minutes, flipping halfway through, until lightly browned. Don’t worry if it’s not fully cooked through, it will continue to cook in the soup.
Transfer the cooked meatballs into the crockpot and add the celery, carrots, onion, garlic, beef broth, petite diced tomatoes with liquid, Worcestershire sauce, Italian seasoning, salt and pepper. Top with bay leaf.
Cover and cook for 6-8 hours on low or 3-4 hours on high, or until the meatballs reach a minimal internal temperature of 145°F.
In the last hour of cooking, add the dried pasta and cook until pasta is tender.
Add the fresh spinach leaves and cook until wilted.
