✔ Updated · fixed card times + storage and reheating guide
This old-fashioned potato soup is the simple kind my mum made in Ohio: potatoes, butter-cooked onion, milk, salt and pepper. Half the potatoes are mashed right in the pot, so it thickens naturally with no flour.
At a glance
The one tip that matters: Heat the milk gently and never let the soup boil, then mash half the potatoes so the soup thickens itself.
Why You'll Love This Potato Soup
- Just 5 main ingredients: potatoes, butter, onion, milk, salt and pepper.
- Naturally thick and creamy, with no flour or cream needed.
- Budget-friendly comfort food that reheats well for lunches.
What Makes Potato Soup Old-Fashioned?
Old-fashioned potato soup is farmhouse cooking at its simplest, and I still make it on the first cold night of the year. Instead of a flour roux, cream or cheese, it relies on the potatoes themselves: once they are tender, mashing about half of them releases their starch, which thickens the milk into a creamy, spoonable soup with chunks of potato throughout.
| Old-fashioned potato soup | Modern loaded potato soup | |
|---|---|---|
| Ingredients | Potatoes, onion, butter, milk, salt, pepper | Adds broth, garlic, celery, carrots, bacon, cheese, sour cream, herbs |
| Thickener | Mashed potato starch | Often a flour roux, cream or cheese |
| Texture | Creamy and chunky, lighter body | Thicker and richer, often blended smooth |
| Time | About 50 minutes | Often 1 hour or more |
| Flavor | Clean potato, sweet onion and butter | Smoky, cheesy and heavily seasoned |
Step-by-Step Photos
Here's how it comes together. Exact amounts, times and temperatures are in the recipe card below.
Tips for Success
- Pick a starchy potato. Russets break down easily and make the creamiest soup, and they are what I use. Yukon Golds hold their shape a little better and taste buttery. Waxy red potatoes stay firm and won't thicken the soup as much.
- Cut even pieces. Dice the potatoes to about 3/4 inch so they all cook at the same rate, with no hard centers.
- Go slow with the onion. With so few ingredients, slowly cooking the onion in butter until soft and golden gives the soup most of its flavor.
- Never boil the milk. Heat it gently until small bubbles appear around the edge. A hard boil can make the milk separate or scorch on the bottom of the pot.
- Save the potato water. The starchy cooking water thins the soup without diluting the flavor, especially when reheating leftovers that have thickened.
- Season at the end. Potatoes absorb a lot of salt, so taste once the soup is mashed and add more salt and pepper as needed.
Simple Old-Fashioned Potato Soup
6
servings15
minutes35
minutes50
minutesGrandma-style old-fashioned potato soup made with just potatoes, butter, onion, milk, salt and pepper. The potatoes are boiled, simmered gently in milk with golden butter-cooked onions, then half-mashed so the soup is thick and creamy with tender chunks.
Ingredients
3 1/2 pounds russet or Yukon Gold potatoes, peeled and cut into 3/4-inch dice
1 teaspoon salt for the cooking water
3 tablespoons butter
1 medium yellow onion, diced
6 cups whole milk
1 1/2 teaspoons salt, plus more to taste
1/2 teaspoon ground black pepper, plus more to taste
2 tablespoons chopped fresh chives or parsley, for serving (optional)
Directions
- Put the diced potatoes in a large pot, cover them with cold water by about 1 inch and add 1 teaspoon of salt. Bring to a boil and cook for 10 to 12 minutes, until fork-tender. Scoop out and reserve 1 cup of the cooking water, then drain.
- While the potatoes cook, melt the butter in a Dutch oven or heavy soup pot over medium heat. Add the onion and cook, stirring often, for 8 to 10 minutes, until soft and golden. Lower the heat if the butter starts to darken.
- Add the drained potatoes to the onions, then pour in the milk and add the salt and pepper.
- Heat over medium-low heat, stirring now and then, until small bubbles appear at the edges. Keep it at a gentle simmer, never a full boil, for 10 minutes.
- Mash about half of the potatoes right in the pot with a potato masher, leaving the rest in chunks. The soup will thicken as it stands; thin it with some of the reserved potato water if needed.
- Taste and adjust the salt and pepper, then ladle into bowls and top with chives or parsley, extra black pepper and a small pat of butter if you like.
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Storage and Reheating
- Refrigerate: cool the soup quickly, then store it in airtight containers in the fridge within 2 hours of cooking. It keeps for 3 to 4 days.
- Reheat: warm it gently on the stovetop over medium-low heat, stirring often, or in the microwave in short bursts, stirring between each, until steaming hot and 165°F throughout. Add a splash of milk or the reserved potato water if it has thickened.
- Freeze: milk-based potato soup can turn a little grainy after freezing, but it is still good. Freeze in airtight containers for up to 2 months, thaw overnight in the fridge, then reheat to 165°F and whisk or mash to smooth it out.
- Make ahead: the soup tastes even better the next day, once the flavors settle. Reheat it gently and adjust the seasoning before serving.
Easy Add-Ins and Variations
- Extra creamy: swap 1 cup of the milk for half-and-half or heavy cream.
- Loaded: top bowls with crumbled cooked bacon, shredded cheddar, sour cream and green onions.
- Vegetable: cook a diced celery stalk and a diced carrot with the onion.
- Leek and potato: for a different spin, try our Jamie Oliver-inspired potato, leek and bacon soup.
What to Serve With Potato Soup
- Bread for dunking: Olive Garden-inspired breadsticks or Texas Roadhouse-inspired rolls.
- Something green: Cracker Barrel-inspired green beans or a crisp side salad.
- A hearty pairing: Cracker Barrel-inspired mac and cheese or a grilled cheese sandwich.
- More soups: zuppa Toscana and French onion soup.
Frequently Asked Questions
What is the difference between old-fashioned potato soup and regular potato soup?
Old-fashioned potato soup uses only a few ingredients, usually potatoes, onion, butter, milk, salt and pepper, and is thickened by mashing some of the potatoes. Many modern versions add broth, garlic, celery, bacon, cheese, sour cream or a flour roux for a richer, heavier soup.
How do you thicken old-fashioned potato soup?
Mash more of the potatoes in the pot, or let the soup simmer gently a few minutes longer. For a quicker fix, stir 1 to 2 tablespoons of instant potato flakes into the hot soup, or whisk 1 tablespoon of cornstarch into 2 tablespoons of cold milk and stir it in until thickened.
Why did my potato soup curdle?
Milk can separate if it boils hard or heats too quickly, especially lower-fat milk. Keep the soup at a gentle simmer over medium-low heat and stir often. Whole milk is the most forgiving. If it has separated slightly, mashing and stirring the potatoes back in usually makes it smooth again.
Can I make this potato soup with broth?
Yes. Replace 2 cups of the milk with chicken or vegetable broth for a lighter soup with a more savory flavor, keeping the rest milk so it stays creamy. If using regular broth, reduce the salt and season at the end, because broth adds its own salt.
How long does potato soup last in the fridge?
Cool the soup quickly and refrigerate it in airtight containers within 2 hours. It keeps for 3 to 4 days. Reheat gently on the stovetop or in the microwave, stirring, until it is steaming hot and reaches 165°F, adding a splash of milk or water if it has thickened.
