Mashed potato soup is one of the best ways to use up leftover mashed potatoes. It’s creamy, cheesy, and delicious. It’s basically mashed potatoes in a comforting soup form. Ready in under 30 minutes with just a handful of simple ingredients, this quick and easy recipe is perfect for lunch or dinner after a big holiday dinner, or anytime you have some cold mashed potatoes sitting in your fridge. The best part? No one will be able to tell that there's leftovers in there.
Why You’ll Love Mashed Potato Soup
- It’s oh so creamy with a hint of cheesy. Mashed potatoes have a natural creaminess, and they do their job in this mashed potato soup by creating a wonderful creamy texture like no other. And with Parmesan cheese mixed in and cheddar cheese garnished on top, this mashed potato soup it's beautifully cheesy.
- It’s perfect for a cold night. Mashed potatoes are one of my favorite sides, but they just don’t satisfy the same way as a hot bowl of this mashed potato soup on a chilly evening. Nothing is quite as comforting as potato soup.
- It will fill you up. Potatoes are one of the most satisfying foods that will keep you full—thanks to the presence of an appetite inhibiting protein that’s proven to satiate you.
Ingredients and Substitutions
To make this easy leftover mashed potato soup, you will need the following ingredients (full quantities in the recipe card below):
- all-purpose flour
- vegetable stock - you can also use chicken stock if that’s what you have on hand.
- Italian seasoning - or substitute with dried oregano.
- leftover mashed potatoes - you can use any mashed potato that you have such as Creamy Mashed Potatoes, Mascarpone Mashed Potatoes, Garlic Mashed Potatoes with Sour Cream, or Healthy Mashed Potatoes.
- Parmesan cheese - you can substitute this with asiago cheese or sharp white cheddar for a similar flavor. Consider making it even cheesier by adding other favorites like Pepper Jack, Monterey Jack, mozzarella, or gruyere.
- salt and pepper
- cheddar cheese - to add on top.
You also need some cheddar cheese to add on top, along with any other toppings that you’d like. Make it your own by adding creative garnishes like crumbled bacon, sliced green onions, sour cream, croutons, and more.
How to Make the Best Mashed Potato Soup
- Sauté aromatics. In a large stockpot melt butter over medium-high heat, until it starts to bubble, about 1 minute. Add onion and sauté until soft and tender and starting to brown, about 3-4 minutes.
- Add ingredients. Add flour and mix well until evenly combined with the onion mixture and continue to cook for another minute. Pour in stock and Italian seasoning and mix well. Bring the mixture to a simmer, about 3-4 minutes,
- Add mashed potatoes and simmer. Add in mashed potatoes and Parmesan cheese. Mixing until all the potatoes have broken up and the cheese has melted. Season with salt and pepper to taste. Let the soup simmer over medium heat for 8-10 minutes until thickened to a desired consistency, stirring occasionally.
- Serve. Ladle into bowls and top with shredded cheddar cheese.
Recipe Tips and Tricks
- How to store: Keep leftover mashed potato soup in an airtight container in the refrigerator for up to three to four days.
- How to freeze: Although you can safely freeze mashed potato soup, I don't recommend it. Potatoes break down when frozen and the soup will lose some of its creamy texture, can become grainy, and lose some flavor. If you do want to freeze it, store it in an airtight container or freezer bag and freeze for up to 3 months.
- How to reheat. Reheat mashed potato soup on the stove over medium-low heat until warmed through, about 5-10 minutes. If the soup has thickened up too much in the fridge, add in some water or stock until desired consistency is reached. Season with salt and pepper to taste, if needed.
More Soup Recipes
- Creamy Ham and Potato Soup
- Light Cream of Broccoli Soup
- Creamy Tomato Potato Soup
- Sweet Potato Soup
- Split Pea Soup
- Beef Taco Soup
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