What do you do with leftover mashed potatoes? Most of the time, we just eat them as-is. Until I saw a recipe for leftover mashed potatoes soup, I never even considered another use for leftover mashed potatoes.

So why haven’t I? Honestly, I guess I thought the holiday leftovers were good enough that I didn’t need to do anything to them at all. I was wrong! This leftover mashed potatoes soup with leeks, fennel and garlic is SO good! I’m annoyed with myself for waiting so long to try something new.

We only make mashed potatoes during the holidays. It’s very rare we’d make them other times during the year. On occasion, I do make roasted or smashed potatoes, but hardly ever make mashed potatoes. When we do make mashed potatoes, they are darn good. We add quite a lot of cream and butter to them, so they are decadent and do taste very special for the holidays.

This Anthony Bourdain recipe is the tried and true mashed potatoes recipe we use. But to warn you, it is very rich. Extremely rich. So if you’re not into rich, maybe try something with less butter. The way I look at it – I make mashed potatoes once or maybe twice a year, so I’m going to go all-in.

This potato and leek soup recipe is actually super easy to make. You will need fresh veggies, stock, and some herbs, and that’s it – well – and the leftover mashed potatoes. I used leeks, celery and fennel. But if you don’t have one of those on-hand, I think this recipe would work fine with other veggies – like onions or other root vegetables.

This soup is so delicious! It’s hearty, but not at all heavy. I made it while I had a cold and I found it very soothing and so yummy. If you’ve ever wondered what to do with leftover mashed potatoes, this soup is for you! I promise you won’t be disappointed.

Leftover Mashed Potatoes Soup Recipe

Ingredients:

2 Tbsps olive oil
4 leeks (stalks only), chopped
2 cloves garlic, minced
1 bulb of fennel, chopped
1 stalk of celery, chopped
3 cups mashed potatoes
5 cups chicken stock
4 sprigs of thyme
1 bay leaf

Directions:

Heat oil in a large pot over medium heat. Add leeks, garlic, fennel and celery. Add salt and pepper and cook covered, stirring occasionally, for 15 minutes, or until tender.

Next, add mashed potatoes, broth, thyme, and bay leaf. Mix well and bring to a simmer. Cook for 5-10 minutes to meld the flavors.

Remove thyme and bay leaf. Use an immersion blender to puree the vegetables or pour the soup mixture into a blender or food processor and blend until smooth. Serve with fresh thyme, black pepper and a drizzle of olive oil.