This is a wonderfully easy way to use the last of the holiday mashed potatoes. I hesitate to call this a recipe because I've kept the ingredients list so simple. Take a quick peek and you'll see what I mean. You can obviously expand this base with bacon, other types of cheese and heavy cream if you want a richer soup. I do have  a few cautions that I'd like to share with you. Do not salt this soup until you taste it. The potatoes have already been salted, there is some salt in the broth and the Parmesan cheese contributes still more to the pot. Proceed with caution. Most recipes that use hard grating cheeses don't tell you the method that should be used to obtain the correct quantity. Unless specifically told otherwise, it is best to use the small holes of a box grater when accurate measurement is required. This is a nice soup for cooler winter nights and leftovers can be frozen. I hope you'll give this recipe  a try. While I've made significant changes, the inspiration for this soup was Julia Child's Potage Parmentier. Here's how this version of the soup is made.

Leftover Mashed Potato Soup

Ingredients:

2 cups chopped leeks (white and tender green)

4 cups low-sodium chicken or vegetable broth

3 cups leftover (seasoned) mashed potatoes

1/2 cup (1-oz.) finely grated Parmesan cheese

1/2 to 1 cup whole milk or buttermilk

1/4 teaspoon pepper

Salt to taste

1/4 cup finely chopped parsley or snipped chives

Directions:

Combine chopped leeks and chicken broth in a large saucepan. Bring to a boil over high heat. Reduce heat and simmer, covered, for 30 minutes. Transfer mixture to a blender jar to puree, or use an immersion blender and puree in place. Add potatoes to stock and stir to blend. Add milk and pepper and fold in cheese. Adjust salt to taste. Simmer for 15 minutes longer. Ladle soup into bowls and garnish with chopped parsley or snipped chives. Serve hot. Yield: 6 servings.

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