Mashed potato soup is one of the best ways to use up leftover mashed potatoes. It’s creamy, cheesy, delicious, and ready in under 30 minutes.
- 2 tablespoons butter
- ½ small onion, diced
- 1 tablespoon all-purpose flour
- 2 cups vegetable or chicken stock
- 1 teaspoon Italian seasoning
- 3 cups leftover mashed potatoes
- 1/3 cup Parmesan cheese, freshly grated
- salt and pepper (to taste)
- cheddar cheese, shredded (optional, for topping)
- 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 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 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.
- Ladle into bowls and top with shredded cheddar cheese.
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.
- Prep Time: 5 minutes
- Cook Time: 20 minutes
- Category: Soup
- Method: Stovetop
- Cuisine: American
Keywords: mashed potato soup, leftover mashed potato soup, soup with mashed potato, leftover mashed potato