Julia Child Potato Leek Soup Recipe

Julia Child Potato Leek Soup (Potage Parmentier) is a rustic French soup of potatoes and leeks simmered until tender, then mashed and finished with cream or butter. Julia calls it in Mastering the Art of French Cooking (page 37): “Leek and potato soup smells good, tastes good, and is simplicity itself to make.”

The name “Potage Parmentier” honors Antoine Parmentier, the French pharmacist who convinced skeptical 18th-century France to embrace potatoes. Before him, the French thought potatoes caused leprosy. Thanks to Parmentier, we have this soup.

I make this when I want comfort without fuss. Four ingredients, one pot, zero stress.

What is Potage Parmentier? A classic French leek and potato soup with rustic texture. Mashed by hand, not blended smooth. Serve hot, or chill it to make Vichyssoise.

Why You’ll Love This Recipe

• Four main ingredients: Potatoes, leeks, water, salt. That’s the base. Julia believed simple done well beats complicated done poorly.
• Rustic texture, not baby food: Julia specifically warns against over-blending. A fork or food mill gives it character that a blender destroys.
• Incredibly versatile: Add watercress for watercress soup. Add cream and chill for Vichyssoise. Throw in carrots, broccoli, or cauliflower. This recipe bends to your whims.
• Ready in under an hour: Simmer for 40-50 minutes, mash, finish with cream. Dinner on the table without drama.
• Make-ahead friendly: The soup base can sit uncovered until you’re ready to serve. Just reheat and stir in the cream at the last moment.

Julia Child Potato Leek Soup Ingredients

From Mastering the Art of French Cooking, Vol. 1, Pages 37-38. Serves 6-8 (about 2 quarts).

For the Soup:

• 1 lb potatoes (about 3-4 cups), peeled and sliced or diced
• 1 lb leeks (about 3 cups thinly sliced), including tender green parts
• 2 quarts water
• 1 Tb salt

For Finishing:

• 4-6 Tb whipping cream OR 2-3 Tb softened butter
• 2-3 Tb minced fresh parsley or chives

Potato options: Starchy potatoes like Russets break down beautifully and give the soup body. Yukon Golds work too for a slightly creamier result.

Leek alternatives: No leeks? Yellow onions work. The flavor will be slightly different but still delicious.

How To Make Julia Child Potato Leek Soup

1. Clean the Leeks Thoroughly: Leeks hide dirt between their layers. Slice them first, then soak in a bowl of cold water for a few minutes. Swish around and let the grit sink to the bottom. Lift out the leeks and drain. Repeat if they’re especially dirty.
2. Combine and Simmer: Add the sliced potatoes, cleaned leeks, water, and salt to a large pot. Bring to a boil, then reduce to a simmer. Cover partially and let everything cook for 40 to 50 minutes until the vegetables are completely tender.
3. Mash the Soup: This is important. Use a fork or potato masher to break down the vegetables right in the pot. Or pass the soup through a food mill for a slightly smoother result. Do NOT use a blender. Julia specifically warns against “baby pap” texture. The soup should have rustic character.
4. Taste and Adjust: Check the seasoning. Add more salt if needed. The flavor should be clean and satisfying, not bland.
5. Finish with Cream or Butter: Just before serving, remove the pot from heat. Stir in the cream or butter spoonful by spoonful. This enriches the soup without cooking the dairy.
6. Serve: Ladle into a tureen or individual soup bowls. Scatter minced parsley or chives over the top for color and freshness.

Recipe Tips

• Don’t skip cleaning the leeks. Cut them open and you’ll see layers of grit hiding inside. Dirty leeks make gritty soup. Nobody wants that.
• Mash, don’t blend. Julia is clear about this. A food processor or blender turns this into something unpleasant. Use a fork, potato masher, or food mill.
• Add the cream off the heat. Stirring cold cream into boiling soup can cause curdling. Take the pot off the burner first.
• Make it ahead. The soup base keeps beautifully. Store without the cream. Reheat gently and add cream just before serving.
• This is your canvas. Julia says you can add watercress, carrots, string beans, cauliflower, broccoli, or “anything else you think would go with it.” Experiment freely.

Recipe Variations

• Vichyssoise (Cold Version): To transform this into elegant chilled Vichyssoise, blend the soup smooth (yes, smooth for this one), add extra cream, and chill for at least 4 hours. Serve ice cold with minced chives. We have a separate Vichyssoise recipe for the full method.
• Watercress Soup: Add a bunch of watercress to the simmering soup in the last 5 minutes. Mash or blend. The peppery flavor transforms the entire bowl.

What To Serve With Potato Leek Soup

This soup works as a starter or a light main course. To build a complete meal:

• Crusty French bread for dipping and soaking up every last drop.
• Simple green salad with vinaigrette for freshness.
• Cheese plate if you want something more substantial alongside.
• Roast chicken turns this into a full dinner.

Wine: A crisp white wine like Sauvignon Blanc or a light Chardonnay pairs nicely with the creamy, earthy flavors.

How To Store

• Refrigerator: Store the soup base (without cream or butter) in an airtight container for up to 4 days. Add the cream fresh when you reheat.
• Freezer: Freeze the soup base for up to 3 months. Thaw overnight in the fridge. The texture may be slightly different after freezing, but the flavor holds.
• Reheat: Warm gently over medium-low heat until simmering. Stir in cream or butter just before serving.

Nutrition Facts

Per serving (serves 8):

• Calories: 145 kcal
• Protein: 3g
• Total Fat: 6g
• Saturated Fat: 3g
• Carbohydrates: 22g
• Fiber: 2g
• Sugar: 3g
• Sodium: 590mg
• Cholesterol: 15mg

FAQs

Source: Mastering the Art of French Cooking, Vol. 1 by Julia Child, Pages 37-38

– Claire