Mashed Potato Leek Soup

by Rachel on November 25, 2011

Mashed Potato Soup

Do you have leftover mashed potatoes from Thanksgiving? We always do. My children loved mashed potatoes. I often make them (potatoes, not children) and end up with leftovers – even when it isn’t Thanksgiving. Rather than waste them, or freeze them (again, the potatoes, not the kids), I often turn them into soup. Prepared mashed potatoes are cropping up (I was going to say SPROUTING) everywhere.  You don’t need to admit to me, or anyone else for that matter, if you’ve bought them. Costco’s All Natural Mashed Potatoes aren’t as good as homemade, but they’ll do in a pinch.  In any case you’ll want a batch of mashed potatoes that’s nice and smooth. If yours are, shall we say, ahem lumpy – toss them in the Cuisinart or blender before you add them to this recipe. If you haven’t tried the packs of two trimmed leeks at Trader Joe’s, you should. My personal leek use has sky rocketed since discovering them. I’m pretty sure I’m responsible for at least a 5% increase in their sales. You’re welcome TJ’s. My only disappointment recently was that TJ’s came out with trimmed and peeled shallots in a pack of three – which I adored, and then pulled them from the shelves in a matter of about 8 weeks. That’s what is commonly known as a shallot tease and should be illegal. A girl can get worked up about things like this.

Mashed Potato Leek Soup (serves 6-8)


  • 2 tablespoons butter or olive oil
  • 2 leeks, cut lengthwise and then thinly sliced, white parts only
  • 1 shallot, finely diced
  • 1 ½ cups onions, diced
  • 1 cup dry white wine
  • 3 cups chicken broth (switch to veggie broth for a vegetarian soup)
  • 3 cups smooth mashed potatoes
  • 1 cup whole milk (or skim – it just won’t be quite as creamy)
  • 1 cup grated Parmesan cheese
  • ¼ teaspoon nutmeg
  • ¼ teaspoon cayenne pepper (if you can’t take any heat cut this in half, or eliminate entirely)


  • 2 zucchini, sliced lengthwise about ½ inch thick
  • 1 red bell pepper, cut in long wide strips
  • 2 tablespoons olive oil
  • kosher salt and freshly ground pepper

Preheat your oven to 400 degrees.

In a large soup pot heat the butter on medium heat. Add the leeks, shallot and onions and sauté until they are soft but not browned, about 10-12 minutes.  Add the dry white wine, bring to a simmer and cook for 2 minutes. Add one cup of chicken stock. Turn off the heat. Using a ladle place all of the onion/leek/shallot mixture, including the broth and wine, in a blender. Process until very smooth.

Pour the smooth soup back into your soup pot.  Add the remaining soup ingredients (chicken broth, potatoes, milk, cheese, nutmeg and cayenne). Stir over medium heat until everything is blended and the cheese has melted.  Leave on low heat while you assemble the vegetable garnish.

Put a small amount of olive oil on a sheet pan.  Spread out the zucchini and bell peppers on the pan. Using a basting brush, lightly coat the zucchini and peppers with olive oil. Sprinkle with kosher salt and pepper. Place in the hot oven and roast the vegetables until they are just cooked through, about 10-12 minutes. Remove from oven, place on cutting board and chop them into small cubes.

Serve the soup garnished with a generous serving of the roasted vegetables.

{ 1 comment… read it below or add one }

plasterers bristol August 23, 2015 at 10:43 pm

Great recipe. Top marks. Thanks for posting this.


Leave a Comment

{ 1 trackback }

Previous post:

Next post: