How to Make the Best Leek and Potato Soup at Home
Leek and potato soup is one of my favorite British-style comfort foods. It’s thick and creamy, with rich flavor from homemade chicken stock, and finished with crunchy croutons and a sprinkle of sharp Cheddar cheese. You can easily make it a hearty one-pot meal by stirring in sliced sausage or leftover ground beef. Leeks are such an underrated vegetable—milder and sweeter than onions, and when sautéed in butter they bring a wonderful depth of flavor to any soup or stew. In this post, I’ll walk you through how to make this classic soup, how to adapt it for the crockpot, and share my favorite tips for making any soup taste extra delicious.
What is Potato Leek Soup Made Of?
Wondering what potato leek soup is made of? Aside from the obvious leeks and potatoes, this version also includes onions (which complement the leeks beautifully), homemade chicken stock, and a spoonful of crème fraîche. I like using chicken stock for its mild, balanced flavor, but any good stock will work (I often use beef, lamb, or turkey stock as a base for my soups). The crème fraîche adds a gentle tang, though you can easily swap it for thick cream if that’s what you have on hand. And if you’d like to keep it dairy-free, simply leave out the cream altogether—the potatoes add plenty of body, so the soup stays velvety and satisfying even when no cream is added.
Ingredients You’ll Need
How to Make the Best Leek and Potato Soup (Step-by-Step)
Step 1
In a medium pot, melt the butter over medium heat. Add the leeks and onions and sauté until softened, about 5–7 minutes. Season with 1 teaspoon of salt and 1/4 teaspoon of black pepper.
Step 2
Stir in the potatoes and pour in 4 cups of stock. Add the remaining salt. Bring to a boil, then reduce to a gentle simmer. Cook for 20 minutes, or until the potatoes are tender, then take the soup off the heat and stir in the crème fraîche (or thick cream if you prefer it).
Step 3
Using a stick blender, blend the soup until smooth (or until chunky if you prefer it that way). If it’s too thick, add a little more stock (up to 1 cup). Taste and adjust seasoning as needed.
Step 4
If you would like to make homemade croutons, cut a couple of slices of sourdough into cubes (you can use old bread for this if you like). Toast them in 2 teaspoons of butter in a frying pan, stirring occasionally, until golden and crispy (about 3–5 minutes).
Step 5
Ladle your soup into bowls and serve hot. Garnish with croutons, grated cheddar, and a sprinkle of fresh parsley for color if you like. I like to make this soup quite thick because then the cheddar and the croutons stay nicely on top instead of trying to sink into the soup!
Crock Pot / Make-Ahead Instructions
- In a skillet, melt the butter over medium heat. Sauté the leeks and onions until softened, about 5 minutes. (Optional: you can skip this step and add them straight to the crockpot, but sautéing adds more flavor.)
- Transfer the leeks and onions to the crockpot. Add the potatoes, 4 cups of stock, 1 1/2 teaspoons salt, and a pinch of pepper. Stir well.
- Cover and cook on Low for 6–7 hours or High for 3–4 hours, until the potatoes are very soft.
- Turn off the heat and stir in the crème fraîche.
- Blend the soup with an immersion blender until smooth. If it’s too thick, add a splash of extra stock. Taste and adjust seasoning.
- Serve hot with croutons, grated cheddar, and a sprinkle of fresh parsley if desired.
Secrets to Flavorful Soup (How to Make Soup Taste Delicious)
- Start by sautéing the aromatics (in this case the leeks and onions) in butter. This adds lots of flavor to any soup. Apart from leeks and onions, other aromatics often added to soups are garlic, carrots and celery – and they all benefit from being sauteéd in butter (or other healthy fat).
- Use homemade stock if possible.
- Season little and often, not just at the end of cooking. It is hard to adjust salt at the end of cooking if you haven’t added any at the start.
- Add enough salt, otherwise the soup will taste bland. Also use freshly ground black pepper if you can.
- Add some creme fraiche or thick cream to the finished soup – it makes the soup extra smooth and creamy.
Serving Suggestions
- This soup can be served with some buttered sourdough bread, homemade pizza or some freshly baked dinner rolls.
- My favorite garnish for leek and potato soup is croutons and grated cheddar, but you could also top it with a drizzle of olive oil or cream, chopped chives or parsley.
- To make this soup into a one pot meal, you could add in some leftover cooked ground beef or sliced sausage.
Recipe FAQs
Conclusion
I hope you’ll enjoy this warming leek and potato soup as much as I do. I’m a bit of a soup enthusiast and love experimenting with new recipes, but this one is a true cold-weather classic. It’s especially comforting served with crunchy croutons or a slice of garlic bread fresh from the oven. I first learned to make it while living on the east coast of Scotland, where the winters are long, cold, and blustery—and it’s been a regular part of my kitchen repertoire ever since.
More Cozy Soup Recipes on the Blog:
Barley Soup with Chicken Hearts
Hearty Green Lentil and Broad Bean Soup
Traditional Sausage and Bean Soup
Nourishing Broccoli Soup with Crème Fraîche
The Best Potato and Leek Soup
Equipment
- immersion blender
Ingredients
- 2 tbsp butter
- 1½ cups thinly sliced leeks (only the white and light green parts)
- 1½ cups chopped onions
- 3 cups peeled and diced potatoes
- 4-5 cups chicken stock
- ¼ cup crème fraîche or thick cream
- 1½ tsp unrefined salt, or to taste
- ¼ tsp freshly ground black pepper
To serve
- ⅓ cup finely grated sharp cheddar
- 1 cup sourdough croutons
- ⅓ cup chopped fresh parsley (optional)
Instructions
- In a medium pot, melt the butter over medium heat. Add the leeks and onions and sauté until softened, about 5 minutes. Season with 1 teaspoon of salt and a pinch of pepper.
- Stir in the potatoes and pour in 4 cups of stock. Add the remaining salt.
- Bring to a boil, then reduce to a gentle simmer. Cook for 20 minutes, or until the potatoes are tender.
- Remove from the heat and stir in the crème fraîche.
- Using a stick blender, blend the soup until smooth. If it’s too thick, add a little more stock (up to 1 cup). Taste and adjust seasoning as needed.
- Ladle into bowls and serve hot. Garnish with croutons, grated cheddar, and a sprinkle of fresh parsley for color.
Notes
- Use only the white and light green parts of the leeks; save the dark green tops for making stock.
- For extra flavor, you can sauté the onions and leeks in chicken fat skimmed from your stock instead of butter.
- A thicker soup helps croutons and grated cheese stay on top for better presentation.
- To make croutons: cut a couple of slices of sourdough into cubes (you can use old bread for this if you like). Toast them in 2 teaspoons of butter in a frying pan, stirring occasionally, until golden and crispy (about 3–5 minutes).
