This simple Irish Potato Leek Soup has only FOUR ingredients and comes together in only 30 minutes! There's no milk or cream in this recipe- just leeks, potatoes, stock, and plenty of butter.
Melt 6 tablespoons of the butter in a large pot over medium heat.
Add the leeks, stir to coat in the butter. Cook for approximately 10 minutes over medium heat, stirring occasionally but not too frequently, until the leeks are meltingly tender and soft. You don't want them to brown- if they are browning, turn down the heat.
While the leeks are cooking, peel and dice the potatoes (2 lbs.) into 1/2" pieces. Tip: The smaller the pieces are diced, the shorter time the soup will take to cook.
After the leeks are cooked, add the peeled and diced potatoes, chicken broth (4 cups), and some kosher salt and black pepper. Use more salt if you are using unsalted butter and/or low sodium chicken stock. Bring to a boil.
Cover, turn the heat to low, and simmer for 10-15 more minutes, until potatoes are cooked through (use the tines of a fork to test the potatoes - if they pierce them very easily, the potatoes are done).
Use an immersion blender to puree the soup directly in the pot. Alternatively, you can blend it in batches using a standing blender, or you can use a potato masher for a more rustic, lumpy texture.
Turn off heat and stir in the remaining 2 tablespoons of butter until melted. Taste and adjust seasoning if necessary. Tip: Don't be shy with the salt - this soup needs plenty of it!
Serve topped with chopped fresh chives, cracked black pepper, crumbled bacon, and/or sour cream, if desired.
Notes
Time saving tip: If you don't care about super smooth soup, I recommend using white potatoes. You can keep the skin on, since it's thinner, so you won't have to worry about peeling them. Just give them a good wash with a scrubbing brush.
Don't skimp on the salt! Potatoes are bland and need a lot of it. I didn't include the exact amount since it will vary depending on the broth and butter you use, so you'll have to taste and adjust according to your preference. But if you think it's a bit bland, chances are, you just need to add some salt.
To wash the leeks, trim the dark green parts off. Then, halve them lengthwise and slice them into 1/4" pieces. Place all the cut leeks into a large container and cover with cold water. Use your hands to separate the leeks out as much as possible. Then, use a slotted spoon to lift them out of the water and transfer them to a colander (the dirt will sink to the bottom of the container). Give them one final rinse in the colander and you're good to go!
A note on the butter: While I recommend using butter with abandon here, you can make a lighter version by using 4 tablespoons, or even 2 tablespoons, of butter if you want. If you do this, I recommend adding some half and half or whole milk at the end to make it a little richer and creamier.
To make this dairy free, just use ghee instead of butter.
To make this vegetarian, make sure to use vegetable stock instead of chicken.
For a vegan option, you can use 2 tablespoons of olive oil in place of the butter, then stir in 2 more tablespoons at the end after cooking.
Freeze in an airtight container for up to 3 months.