Slow Cooker Cheesy Potato and Ham Chowder

Ingredients:
1 1/2 lbs. russet potatoes, peeled and diced into 1/2" cubes (about 3 medium sized potatoes)
 4 cups cubed ham 
 4  celery, diced
  1 t minced garlic
1/2 tsp black pepper
4 cups chicken stock (or broth)
2 cups Whole Milk
2 Tbsp cornstarch
2 cups shredded cheddar cheese
1 cup sour cream
2 Tbsp fresh minced parsley
extra parsley, pepper and cheese, for garnish

Instructions

1. To a 6 qt slow cooker,  (potatoes through and including chicken stock).  Stir, cover, and cook on LOW for 8-10 hours, until potatoes are tender.
2. In a small mixing bowl, whisk milk and cornstarch until smooth.  Stir into soup in slow cooker, cover and cook on HIGH 20-25 minutes until thickened, stirring occasionally.  Turn off heat, stir in cheese, sour cream and parsley until cheese is melted.
3. Serve sprinkled with extra cheese, black pepper and parsley if desired.