Penny’s Butternut Squash Soup

6 Tablespoons salted butter
6 cups of cooked butternut squash cut into 2-inch cubes (about 3 pounds of uncooked squash)
2 cups chopped leeks (use white and pale green section only)
1 cup chopped celery
1 cup chopped Granny Smith apples (for tartness)
1 cup peeled and diced carrots
2 Tablespoons dried thyme
2 teaspoons dried sage
6 cups low sodium chicken broth (boxed broth preferred)
1 cup apple cider
1 cup sour cream
Crème fraiche (for garnish – usually in the cheese department)
Fresh chives and sage (for garnish)