Equipment
Ingredients
Vegetables
- 300 g leeks, white and light green parts only, sliced
- 400 g russet potatoes, peeled and diced
Base and Dairy
- 50 g unsalted butter
- 800 ml vegetable broth
- 150 ml heavy cream, chilled
Seasoning and Garnish
- 10 g kosher salt
- 2 g white pepper, finely ground
- 10 g fresh chives, finely minced
Nutrition (per serving)
Method
Submerge the sliced leeks in a bowl of cold water. Agitate them to release any dirt, let the dirt settle to the bottom, and carefully lift the leeks out. Drain completely.
Melt the unsalted butter in a heavy-bottomed pot over medium-low heat. Add the cleaned leeks and saute gently until soft and translucent, about 10 minutes. Do not let them take on any brown color, as this will ruin the pure pale aesthetic of the soup.
Add the diced potatoes, vegetable broth, and kosher salt. Bring to a gentle boil at 100°C/212°F, then reduce the heat to maintain a steady simmer at around 90°C/195°F. Cook until the potatoes are completely tender and easily crushed against the side of the pot.
Remove the pot from the heat. Carefully transfer the hot soup to a blender in batches, and puree until completely smooth.
Pass the pureed soup through a fine mesh strainer into a clean bowl, using a ladle or spoon to press it through. This step is essential for the classic silky texture.
Whisk in the heavy cream and white pepper. Cover the bowl and chill in the refrigerator until completely cold, at least 4 hours.
Taste the chilled soup and adjust the salt if necessary, as cold temperatures dull flavor perception. Ladle into chilled bowls and garnish with minced fresh chives.
Chef's Notes
- Using white pepper instead of black pepper is a classic French technique to maintain a pristine, unblemished color in light-colored sauces and soups.
- The choice of potato matters. Russet or starchy potatoes will give a fluffier, lighter texture when blended, whereas waxy potatoes can turn slightly gluey if overworked.
- Do not skip the straining step. The fibrous nature of leeks means that even high-powered blenders leave microscopic fibers behind. Straining is what elevates this from rustic to refined.
- For an extra touch of elegance, chill your serving bowls in the refrigerator for 30 minutes before plating.
Storage
Refrigerator: 3 days — Store in an airtight container to prevent absorbing refrigerator odors. Keep cream incorporated.
