Ever stare at a container of leftover mashed potatoes and wonder if they can be transformed into something truly spectacular? The answer is a resounding yes! This Leftover Mashed Potato Soup recipe is the ultimate way to breathe new life into your leftovers. It turns a simple side dish into a creamy, rich, and deeply satisfying meal that tastes like it simmered for hours, even though it comes together in under 30 minutes. It’s the perfect cozy dinner for a chilly evening.

Why You’ll Love This Leftover Mashed Potato Soup Recipe
Beyond being incredibly delicious, this recipe is a true kitchen hero. It’s a fantastic way to reduce food waste, especially after holidays like Thanksgiving or Christmas. Here’s why it will become your new favorite:
- Incredibly Fast: Since the potatoes are already cooked and mashed, you skip the longest part of making potato soup. This dish goes from stovetop to table in record time.
- Budget-Friendly: You’re using leftovers as the base, making this an exceptionally economical meal.
- Fully Customizable: Treat this recipe as a blank canvas. Keep it simple and creamy, or load it up with your favorite baked potato toppings.
- Ultimate Comfort Food: Rich, warm, and creamy, this soup delivers all the comforting flavors you crave. For another comforting soup, try this Creamy Chicken Parmesan Soup.
The Key Ingredients for Your Potato Soup
The beauty of this soup lies in its simplicity. You only need a handful of pantry staples to create something magical.

- Butter: Used for sautéing the aromatics and adding a layer of rich flavor.
- Onion & Garlic: The essential flavor base that gives the soup its savory depth.
- Chicken or Vegetable Broth: This thins the mashed potatoes to the perfect soup consistency. Use a low-sodium version to control the saltiness.
- Leftover Mashed Potatoes: The star of the show! About 4 cups are needed. The consistency of your original mashed potatoes will affect how much broth you’ll need. Don’t worry if they are seasoned with garlic or cheese—that just adds more flavor! If you need a great base recipe, try these creamy mashed potatoes (coming soon).
- Heavy Cream: This is the secret to an ultra-creamy, luxurious texture.
- Cheddar Cheese: Sharp cheddar provides the best flavor, melting beautifully into the soup.
- Salt & Black Pepper: Adjust to your taste, especially since your mashed potatoes are likely already seasoned.
Step-by-Step Instructions to Make Creamy Mashed Potato Soup
Follow these simple steps to transform your leftovers into a delicious soup.
- Sauté Aromatics: In a large pot or Dutch oven, melt the butter over medium heat. Add the chopped onion and cook until softened and translucent, about 5-6 minutes. Stir in the minced garlic and cook for another minute until fragrant.
- Combine Ingredients: Add the leftover mashed potatoes and the chicken broth to the pot. Stir everything together until the mashed potatoes begin to dissolve into the broth.
- Simmer the Soup: Bring the mixture to a gentle simmer, stirring occasionally to prevent sticking. Let it cook for about 10 minutes to allow the flavors to meld together. If you prefer a completely smooth soup, use an immersion blender at this stage to puree any lumps.
- Add Cream and Cheese: Reduce the heat to low and slowly stir in the heavy cream and shredded cheddar cheese. Continue stirring until the cheese is completely melted and the soup is smooth. Do not let the soup boil after adding the dairy, as it can cause it to separate.
- Season and Serve: Taste the soup and season with salt and pepper as needed. Ladle the hot soup into bowls and garnish with your favorite toppings.
Tips for the Best Creamy Potato Soup
A few simple tips can take your Leftover Mashed Potato Soup from great to absolutely amazing.
- Adjusting Consistency: If your soup is too thick, add more broth a little at a time until you reach your desired consistency. If it’s too thin, let it simmer a bit longer or create a small slurry with a tablespoon of cornstarch and a little cold water to thicken it up.
- Taste Before Seasoning: Your mashed potatoes are already seasoned, so taste the soup before adding any extra salt.
- Use Quality Cheese: For the smoothest melt and best flavor, shred your own cheese from a block. Pre-shredded cheeses often contain anti-caking agents that can make the soup grainy.
Fun Variations and Add-Ins
This recipe is wonderfully versatile. Try these additions to make it your own.
- Add Protein: Stir in cooked, shredded chicken, crumbled sausage, or diced ham for a heartier meal. A dish like this Salisbury Steak (coming soon) would pair wonderfully on the side.
- Spice it Up: Add a pinch of cayenne pepper, a dash of hot sauce, or some chopped jalapeños for a spicy kick.
- Add Vegetables: Stir in some steamed broccoli florets, corn, or sautéed mushrooms for extra texture and nutrition.
Best Toppings for Loaded Potato Soup
Toppings are where you can really have fun. Set up a toppings bar and let everyone customize their own bowl!
- Crispy crumbled bacon
- Sliced green onions or chives
- A dollop of sour cream or Greek yogurt
- Extra shredded cheddar cheese
- Croutons or crispy fried onions
Storing, Freezing, and Reheating
This soup makes for fantastic leftovers (again!). Here’s how to store it properly.
- Storing: Keep leftover soup in an airtight container in the refrigerator for up to 4 days.
- Reheating: Gently reheat the soup on the stovetop over low heat, stirring frequently. Avoid microwaving, as it can sometimes cause creamy soups to separate.
- Freezing: Dairy-based soups can sometimes change texture upon freezing. If you plan to freeze it, you may want to leave out the cream and cheese. Freeze the base, and then add the dairy and cheese when you reheat it for the best results.
FAQs about Leftover Mashed Potato Soup
Absolutely. To make it vegan, ensure your leftover mashed potatoes are dairy-free. Use vegetable broth, sauté the onions in olive oil instead of butter, and substitute the heavy cream and cheese with your favorite dairy-free alternatives like full-fat oat milk and vegan cheddar.
Yes, you can use prepared instant mashed potatoes as a substitute. The recipe will work just as well. Simply follow the instructions using the instant potatoes in place of traditional leftovers.
Store the soup in an airtight container in the refrigerator for up to 4 days. Reheat it gently in a saucepan over low heat, stirring often to prevent scorching and ensure it heats evenly. Avoid boiling.
If your soup is too thin, you can let it simmer on low heat to reduce and thicken naturally. For a quicker method, create a slurry by mixing one tablespoon of cornstarch with two tablespoons of cold water, then slowly whisk it into the simmering soup until it reaches your desired thickness.
The best toppings are similar to those for a loaded baked potato. We recommend crispy crumbled bacon, shredded sharp cheddar cheese, sliced green onions or fresh chives, and a dollop of sour cream or plain Greek yogurt.
The Perfect Way to Reinvent Leftovers
This Leftover Mashed Potato Soup is more than just a recipe; it’s a strategy for making the most of what you have. It’s a testament to how simple ingredients can create something truly comforting and delicious. Give this recipe a try, and you’ll never look at leftover mashed potatoes the same way again.
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Leftover Mashed Potato Soup Recipe

Leftover Mashed Potato Soup (The Ultimate Comfort Recipe)
Ingredients
Equipment
Method
- In a large pot or Dutch oven, melt the butter over medium heat. Add the chopped onion and cook until softened, about 5-6 minutes. Stir in the minced garlic and cook for 1 minute more until fragrant.
- Add the leftover mashed potatoes and chicken broth to the pot. Stir to combine, breaking up the potatoes as they warm.
- Bring the mixture to a simmer and cook for 10 minutes, stirring occasionally. For a smoother texture, use an immersion blender to puree the soup.
- Reduce the heat to low. Slowly stir in the heavy cream and shredded cheddar cheese until the cheese is fully melted. Do not let the soup boil.
- Taste the soup and season with salt and pepper as needed. Serve hot, garnished with bacon, green onions, and sour cream if desired.
Notes
For best results, use freshly shredded cheese from a block to ensure a smooth, creamy melt.
Taste the soup before adding salt, as both the mashed potatoes and broth contain sodium.




