Potato Soup w/ Leftover Mashed Potatoes

For the love of mashed potatoes, please oh please stop throwing them away. They're super simple to turn into a baked potato soup and half the work is already done for you.
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By Dylan Clay
December 2, 2025

Stuff You Need

  • ~4-5 cups Leftover Mashed Potatoes
  • 1 box (4 cups) chicken broth
  • 1 cup whole milk
  • 1-2 tbsp sour cream (to taste)
  • 1/4-1/3 cup sharp cheddar cheese (to taste)
  • 2 medium vidalia onions, rough chopped
  • 1 tbsp olive oil
  • 1/4 tsp celery salt
  • 1 package turkey bacon (or regular bacon)
  • 1/2 tsp chicken bullion
  • 1 tsp dehydrated garlic (or 1/2 tsp garlic powder)
  • 1 tsp dried thyme

Set Your Oven to 375F

Line a baking sheet with aluminum foil and cook your bacon.

I had a package of turkey bacon in my fridge so that’s what I used; Allow to cook until you’re happy with the consistency.

I like to season the tops of the bacon with pepper; This is totally optional.

By the time the soup is thickened, the bacon should be done.

Grab a Medium Pot and Set Your Burner to Medium-low Heat

Add 1 tbsp olive oil to the pot.

Rough chop 2 medium Vidalia onions.

My family really loves onions – if you just “kinda” like them, only use 1 onion.

Season with 1/4 tsp celery salt and 1/4 tsp black pepper.

Allow to sauté for ~5-7 minutes until browned. Once browned, add your 1 tsp of dehydrated garlic and 1 tsp dried thyme; Allow to sautee until fragrant (~30 seconds).

Then add your 4 cups of chicken broth – use a wooden spoon to scrape up any fond from the bottom of the pot.

Add the Mashed Potatoes and Mix Well

A large whisk really helps here to break up the potatoes.

Once combined, add the following to the pot:

  • 1 cup whole milk
  • 1 tbsp sour cream (to taste)
  • 1/4 cup sharp cheddar cheese
  • 1/2 the bacon cut into strips
  • 1/2 tsp chicken bullion

Bring this mixture to a slight boil and reduce to a simmer.

The onions here are your first indicator that you’re reaching consistency as they’ll float to the top instead of being stuck at the bottom.

At first the soup will also taste a little grainy from the mashed potatoes but this will sus itself out after simmering.

This is usually after ~15 minutes.

After 15 minutes taste and season with salt, pepper or add more butter, more cheese, more sour cream etc. until you’re happy.

Finish the Soup

From here, garnish with whatever you see fit.

I like to add more cheese, more bacon strips, and a dollop of sour cream.

Potato Soup w/ Leftover Mashed Potatoes

For the love of mashed potatoes, please oh please stop throwing them away. They’re super simple to turn into a baked potato soup and half the work is already done for you.
Prep Time: 5 minutes
Cook Time: 25 minutes
Total Time: 30 minutes

Ingredients

  • ~4-5 cups Leftover Mashed Potatoes
  • 1 box chicken broth 4 cups
  • 1 cup whole milk
  • 1-2 tbsp sour cream to taste
  • 1/4-1/3 cup sharp cheddar cheese to taste
  • 2 medium vidalia onions rough chopped
  • 1 tbsp olive oil
  • 1/4 tsp celery salt
  • 1 package turkey bacon or regular bacon
  • 1/2 tsp chicken bullion
  • 1 tsp dehydrated garlic or 1/2 tsp garlic powder
  • 1 tsp dried thyme

Instructions

  • Preheat oven to 375F and cook bacon on foil-lined baking sheet until crisp.
    1 package turkey bacon
  • Heat olive oil in medium pot over medium-low heat. Sauté chopped onions with celery salt and black pepper for 5-7 minutes.
    1 tbsp olive oil, 1/4 tsp celery salt, 2 medium vidalia onions
  • Add garlic and thyme, cook 30 seconds. Pour in chicken broth, scrape pot bottom.
    1 box chicken broth, 1 tsp dried thyme, 1 tsp dehydrated garlic
  • Whisk in mashed potatoes until smooth. Add milk, sour cream, cheese, half the bacon, and chicken bullion.
    ~4-5 cups Leftover Mashed Potatoes, 1 cup whole milk, 1-2 tbsp sour cream, 1/4-1/3 cup sharp cheddar cheese, 1/2 tsp chicken bullion
  • Bring to slight boil, then simmer 15 minutes. Stir occasionally and adjust seasoning to taste.
  • Garnish with extra cheese, bacon strips, and sour cream.

Notes

If you aren’t a huge fan of onions, use 1 instead. My family loves onions so I use 2 medium or 1 large. 

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