How to Make Potage Parmentier

Julia Child’s first recipe in Mastering the Art of French Cooking (Vol. 1) is a recipe for Potage Parmentier (Leek or Onion and Potato Soup).

It’s smooth, creamy, and has a real depth of flavor. Traditionally this is a leek and potato soup, but if leeks are not available, onions can be easily substituted. This potato leek soup is simple, quick to make, healthy, and oh-so tasty.

Potage Parmentier Recipe

Potage Parmentier Ingredients

• 8 cups cold water
• 8 medium potatoes, washed peeled, and diced
• 2 leeks, washed and thinly sliced (white and light green parts) OR 2 large onions, diced
• 1 tablespoon coarse kosher salt
• White pepper (to taste)
• 1/4 cup heavy cream or 2 tablespoons butter
• 1/4 cup fresh chives, chopped

Potage Parmentier Instructions

1. Add the potatoes, sliced leeks (or diced onions), and 1 tablespoon salt in a soup pot and add 8 cups of cold water.
2. Bring to a boil and immediately reduce to a simmer. Simmer for 45 minutes or simmer until the potatoes are tender.
3. Take the soup off the heat and puree it with a hand immersion blender until smooth.
4. Taste and adjust seasoning if needed with salt and pepper. Use white pepper to keep the pristine look of the soup.**
5. Stir in the cream or butter.
6. Ladle into soup bowls and garnish with chopped chives.

**Make Ahead Note:

To make this leek or onion and potato soup ahead of time, stop after Step 4. At this point, it can be refrigerated in an airtight container for up to 3 days. It can also be frozen for 3 to 4 months.

To complete the soup, bring it up to heat and simmer for 5-10 minutes. Remove it from heat, stir in the cream or butter, garnish with chives, and serve.

Special Equipment

To make this soup as creamy as possible, the easiest tool to use is a hand immersion blender.

If that is not available, allow the soup to cool and blitz it in a stand blender (crack the lid to avoid an explosion). If you want to rock it old school, a food mill works well too.

If none of these are available, strain out the leeks and onions. Then mash the potatoes with a fork and stir them into the soup.

What kind of Potatoes should you use?

Waxy potatoes are best to use when making soup, such as Yukon Golds. Red-skinned potatoes can also be used but they tend to run small and are hard to peel. Look for potatoes that have smooth waxy skin.

Russet potatoes are great for baking but not great for making soups. They tend to make the soup granular instead of a smooth creamy texture.

Cleaning leeks

If you are not accustomed to working with leeks, there is one thing you must know. They must be washed thoroughly.

To do this, cut off the tough dark green leaves and stringy roots. Then cut the white and light tender green stalk lengthwise and rinse in between the layers. Make sure to remove any grit.

Why use cold water?

When you boil vegetables (particularly potatoes) in HOT water, the outside cooks faster than the inside. This uneven cooking results in a lumpy soup.

If the potatoes are placed in cold water and brought to a boil, they’ll cook evenly all the way through. Then when the tubers are puréed, the soup will be smooth and creamy.

Leek or Onion and Potato Soup Variations

This soup is as versatile as it is delicious. Chill it and it transforms into vichyssoise. Or simply add your favorite vegetables and boil them with the potatoes and onions. Vegetables like spinach, watercress, broccoli, asparagus, cauliflower, turnips, peas, and carrots work very well.

Other Soups Inspired by Mastering the Art of French Cooking Vol. 1

Soupe au Pistou

French Onion Soup