Julia’s Potato Leek Soup Adapted for the Slow Cooker

Sunday August 24, 2014

Potato Leek Soup is the workhorse of the French kitchen and has sustained many a soul on a cold night. What is quite remarkable is that you put a potato, a leek, cover with water and it just cooks up into the delicious soup.  This was the first recipe I made out of my copy of Mastering the Art of French Cooking by Julia Child in the 1970s.  It is so simple it is embarrassing and the base for many variations (following), just as tasty.  If you want to make a classic French soup called potage a la bonne femme, the good wife’s soup, just add a handful of chopped fresh chervil at the end of cooking.  Leeks are milder in taste than regular onions.  You really don’t have to worry about proportions; I use a leek for every potato. Soon you won’t even need a recipe. It tastes just as good made with water as with broth, and you just cook the vegetables until they are mushy, purée, and vôila! Your soup for dinner.

Be sure to clean the leeks well in running water; there can be sand in the layers.

Tip: How to clean leeks: Using a knife, trim 1″ off the top and bottom of the leek.  Cut the leek in half length wise.  Remove and discard (or compost) the outer layer of the leek.  Rinse each layer of the leek under cold water, making sure all dirt is removed.


Cooker: Medium Round or Oval

Machine Setting and Cook Time: Low Heat: 5 to 7 hours

Serves 6


  • 4 medium leeks, hairy root end trimmed and thinly sliced, white only to make about 4 cups
  • 4 medium to large russet potatoes, peeled and diced
  • 4 to 6 cups water, vegetable or chicken broth, to cover
  • Salt, to taste
  • 2 tablespoons unsalted butter


Place the leeks and potatoes in the cooker.  Add the water or broth to the pot, just to cover.  Cover and cook on LOW for 5 to 7 hours, until the potatoes are tender.  Using a hand held immersion blender or transferring to a food processor or blender in batches, purée the soup.  Taste for salt and add the butter.  Ladle the hot soup into bowls and serve immediately with fresh French bread.

Pea and Watercress Potato Leek Soup

  • 1 recipe Potato Leek Soup
  • 1 bunch watercress leaves and tender stems, washed and dried by rolling up in a towel
  • 1 12-ounce package frozen petite peas, thawed

One hour before done, add the watercress and peas to the crock.  Purée the soup and serve immediately; the soup will dull as it sits.  We never strain; we love the bits of green vegetables.

Potato Leek Soup with Sorrel or Spinach

  • 1 recipe Potato Leek Soup
  • 2 to 3 cups well packed sorrel or baby spinach leaves, rinsed
  • 1 cup heavy cream (organic if you can)

One hour before done, add the sorrel or spinach to the crock.  Purée the soup, add the cream, and serve immediately.

Beth’s Cream of Celery Soup

  • 1 recipe Potato Leek Soup
  • 1 bunch celery, end trimmed, chopped with the leaves
  • 1 cup heavy cream (organic if you can)

Add the celery with the leek and potatoes in the crock. Cook as directed.  Purée the soup, add the cream, and serve immediately.

Potato Leek Fennel Soup

  • 1 recipe Potato Leek Soup
  • 1 1/2 pounds (2 bulbs) fennel, quartered, bases cut off, and cut out tough lower core
  • 1/4 cup sour cream or creme fraiche

Add the fennel plus its stalks and leaves with the leek and potatoes in the crock. Cook as directed.  Purée the soup, swirl in the sour cream, and serve immediately. You will never regret making this soup. It is divine.

Excerpted from Not Your Mother’s Slow Cooker Cookbook, by Beth Hensperger and Julie Kaufmann. (c) 2005, used by permission from the Harvard Common Press.

Recipe and text copyright Beth Hensperger 2014

Please enjoy the recipe and make it your own. If you copy the recipe and text for internet use, please include my byline and link to my site.

Your Comments

2 comments Comments Feed
  1. Pat 07/09/2014 at 3:30 pm

    I added 2 cans of carnation milk and decreased the water to 2 cups. Also added 3/4 tsp of cayenne pepper. Yum yum good

Leave a Reply