Leek Potato Soup

Ingredients

• 5 cups veg stock
• 4 russet potatoes, peeled and cut into large pieces
• 2 leeks (whites only), thoroughly washed and sliced
• 1-1/2 stalks celery, roughly chopped
• 1 bay leaf
• 1 teaspoons finely chopped fresh thyme
• Salt and freshly ground pepper
• 1/2 cup heavy cream
• 1/4 c. buttermilk