Leek and Potato Soup is a velvety soup based on a Julia Child recipe. Simple ingredients like potatoes, leeks, and butter.

The first time I tried Leek and Potato Soup was at California Pizza Kitchen. I was in junior high, and I had never even heard of a leek! I was glad that I went ahead and tried it because it was such a delicious soup!
My sister sent me this Julia Child recipe several weeks ago after she made it. This was fantastic!
It's the first Julia Child recipe I've ever made and hopefully not the last! It has surprisingly little butter for a Julia Child recipe, and many options so you can personalize the soup to your taste.

Recipe Details
Leeks tend to have sand and grit in between the layers, so it's important to wash them well. The easiest way to do this is to cut off the tough tops and discard. Then cut the lower part into fourths but keep the root end intact. This will allow you to run the layers under water to clean out the sand while not dropping any of the pieces.

After the leeks have been washed, you can just cut through the layers to chop them.

The potatoes are washed, peeled, and chopped.

The leeks are cooked in butter to soften.

Then the flour is blended in cooked for 2 minutes. The pot is removed from heat and hot water incorporated.
The potatoes are added and simmered until cooked through.
The soup can be mashed or pureed. If you prefer a silkier consistency, you may run it through a food mill.
Gluten Free Option
This recipe is naturally gluten free!
📖 Recipe

Leek and Potato Soup
Ingredients
- 3 tablespoons butter
- 3 cups sliced or minced leeks (white parts only, or onions, or a combination of both)
- 3 tablespoons flour
- 2 quarts hot water (or 4 to 6 cups water plus milk added at end of cooking)
- 1 tablespoon salt
- ground black pepper (to taste)
- 1 cup tender green part of the leeks (sliced or minced)
- 4 cups potatoes, peeled, and roughly chopped (about 1 ½)
- ⅓ to ½ cup heavy cream or sour cream
- 2 to 3 tablespoons butter (optional)
- 2 to 3 tablespoon minced fresh parsley and/or chives
Instructions
- Melt butter over moderate heat in a 3- to 4-quart heavy-bottomed saucepan. Stir in the leeks and/or onions, cover pan, and cook slowly for 5 minutes without browning.3 tablespoons butter, 3 cups sliced or minced leeks
- Blend in the flour, and stir over moderate heat for 2 minutes to cook the flour without browning. Remove from heat, let cool a moment, and gradually beat in a cup of hot water. Blend thoroughly with the flour and vegetables, then stir in the rest of the water. Note: If you want to use milk, add it at the end of the cooking - it will curdle if you add it now.) I used 6 cups water now and 2 cups milk at the end.3 tablespoons flour
- Stir in the salt and pepper, optional green of leeks, and the potatoes. Bring to a boil, and simmer partially covered for 40 minutes, or until vegetables are thoroughly tender.1 tablespoon salt, ground black pepper, 1 cup tender green part of the leeks, 4 cups potatoes, peeled, and roughly chopped
- For a peasant-type soup, mash the vegetables in the pan with a mixing fork or potato masher. For a smoother texture, put through medium blade of a food mill. I used an immersion blender and it worked perfectly.
- "Final enrichments": To serve the soup, stir in the milk if using, and blend in as much of the cream/sour cream as you wish. Add salt and pepper to taste. Off heat, stir in the extra butter if desired. Decorate each serving with more cream/sour cream and a sprinkling of herbs.
Maria says
I am on a soup kick. This one looks very tasty!
Lisa says
Props for trying the recipe I sent you. Your version looks very tasty! 🙂
Melissa says
This soup brings me back to a time when I was working full time and was attending culinary school and flat broke!!!
I worked at a specialty food store that housed a soup bar and it was the only thing I could afford to eat for lunch. I loved their potato leek soup-I can't wait to try this one.
Megan says
I actually have the CPK version - and although it's really, really good, I know Julia's version is better!
Kerstin says
What a comforting soup, I love leeks!
Unknown says
I don't remember ever eating leeks -- or even encountering them -- when I was younger, but now so many recipes I try have leeks in them. I feel like I'm sort of drawn to them. I'm going to have to try this soup!
Farmgirl Cyn says
I make this soup often during the winter, tho I use homemade chicken stock in place of the water. It is one of my all time favorites!