Melissa Hamilton and Christopher Hirsheimer invented this soup as a way to use up Thanksgiving leftovers -- mashed potatoes and turkey stock -- but created this recipe to allow them to enjoy the soup all winter long. When you clear out your supply of turkey stock, chicken stock, of course, can be substituted. Light but soothing, simple and delicious, this soup, I have no doubt, will be a staple in my kitchen all winter long. —Alexandra Stafford
Turkey neck, giblets, and heart, or two turkey wings
You can make the stock two ways: while the turkey roasts or ahead of time. Either way, place turkey neck, giblets, and heart or two turkey wings into a large pot. Cover with 10 cups of gently salted water. Add the vegetables. Simmer gently for 3 to 4 hours. Strain. Yield should be 8 cups.
Put the potatoes in a pot of salted cold water. Bring to a boil over medium-high heat and cook until very soft, 20 to 30 minutes. Drain off almost all of the water, then mash the potatoes with a potato masher until very smooth, adding the milk and butter as you go.
Stir in enough of the hot turkey stock to make a smooth, velvety soup. Season with salt and pepper. Serve the soup hot with a sprinkling of chopped chives.