Grandma's Hearty Meatball Soup

From Grandma: We had this at a friend's house house recently and enjoyed it very much. I used frozen meatballs from the super market.

Ingredients:
2 cloves chopped garlic
1 1/2 lb lean ground beef
1/2 cup Italian style bread crumbs
1 egg beaten
2 Tb sun- dried tomato pesto 
1/2 tsp salt - divided
1/2 tsp pepper - divided
1 tbsp canola oil
8 oz trinity mix  (fresh diced onions, celery, carrots)
3 cups fresh spinach leaves
2 cans cannellini beans  (15-16 oz) drained
1  (32-oz) box unsalted chicken stock
1/2 cup grated Parmesan cheese


Directions:

1.  Combine ground beef, bread crumbs, eggs, tomato pesto, 1/4 tsp salt & 1/4 tsp pepper until blended. Shape into meatballs (about 25-30). Wash hands.
2. Preheat large stockpot on medium-high 2-3 minutes.  Place oil in pan, then add meatballs (in batches): cook & turn 6-8 minutes or until browned. Remove meatballs from pan and set aside.
3.  Add trinity mix and garlic to pan; cook & stir 2-3 minutes or until onions softens.  Add spinach, cook 2-3 minutes or until spinach begins to wilt.
4.  Reduce heat to medium-low; stir in beans, stock, meatballs and remaining 1/4 tsp each salt & pepper, simmer 5-7 minutes or until meatballs are heated through and soup is hot.  Top with cheese and serve.