Potato Leek Soup

Ingredients

Equipment Needed

• •Large Dutch oven or heavy-bottomed pot (5-6 quart)
• •Blender or immersion blender
• •Fine-mesh strainer (optional, for ultra-smooth texture)
• •Ladle

Instructions

1. 1

   Clean the leeks thoroughly

   Trim the root ends and dark green tops from your leeks, saving those dark parts for stock if you wish. Halve each leek lengthwise and slice into half-moons about a quarter-inch thick. Transfer to a large bowl of cold water and swish vigorously. Leeks hide dirt between their layers like secrets. Lift the slices out, leaving grit behind, and repeat until the water runs clear. Spin dry in a salad spinner or pat with towels.

   Never dump leeks into a colander to drain. The dirt settles at the bottom of the bowl. Lift the leeks out and the grit stays behind.
2. 2

   Sweat the aromatics

   Melt the butter in a large Dutch oven or heavy-bottomed pot over medium-low heat. Add the leeks and onion, stirring to coat in fat. Here is where patience becomes flavor. Cook gently for fifteen to twenty minutes, stirring occasionally, until the alliums turn completely soft and translucent. You want no color whatsoever. The moment they begin to brown, you've changed the character of your soup. Add the garlic in the final minute, cooking just until fragrant.

   If your leeks begin to sizzle aggressively, reduce the heat immediately. This is sweating, not sautéing. Low and slow extracts sweetness without developing roasted notes.
3. 3

   Add potatoes and stock

   Add the potato cubes to the pot, stirring to combine with the softened leeks. Pour in the stock. It should cover the vegetables by about an inch. If you're short, add water to compensate. Tuck in the bay leaves and thyme sprigs. Season with salt and white pepper. White pepper disappears into the pale soup while black pepper would leave unwanted specks.

   Yukon Golds are ideal here. Their buttery flesh and moderate starch create a naturally creamy texture. Russets work but yield a grainier result. Waxy potatoes won't break down properly.
4. 4

   Simmer until tender

   Bring the liquid to a gentle simmer over medium heat, then reduce to medium-low. Cook uncovered for twenty-five to thirty minutes, until the potatoes offer no resistance when pierced with a paring knife. They should be falling-apart soft. The leeks will have nearly dissolved into the broth. Remove and discard the bay leaves and thyme stems.

5. 5

   Puree to silk

   For the smoothest result, puree in batches using a standard blender, filling no more than halfway and holding a towel over the lid. Hot liquids expand violently and will erupt if you're careless. Blend each batch for a full sixty seconds until absolutely smooth. Alternatively, use an immersion blender directly in the pot, though the texture will be slightly less refined. Return the soup to a clean pot if using a standard blender.

   For restaurant-quality smoothness, pass the pureed soup through a fine-mesh strainer, pressing with a ladle. This extra step removes any remaining fiber and produces an impossibly silky result.
6. 6

   Finish with cream

   Return the soup to medium-low heat. Stir in the heavy cream and warm through for five minutes, but do not let it boil. Taste and adjust seasoning generously. Potato soups can absorb remarkable amounts of salt. The flavor should be round and full, the leek's gentle sweetness balanced by the cream's richness.

7. 7

   Serve properly

   Ladle into warmed bowls. A cold bowl will steal heat from your soup in seconds. Finish each portion with a scattering of fresh chives and a few flakes of good sea salt. For a more elegant presentation, add a small swirl of cream and drag a knife through it. Serve immediately while steam still rises from the surface.

   To serve as vichyssoise, chill the finished soup thoroughly for at least four hours. Taste again before serving cold, as chilling mutes flavors. You'll need more salt and possibly a squeeze of lemon to brighten it.

Chef Tips

• •Build your own stock for this soup when time allows. Simmer chicken backs or a whole carcass with an onion, carrot, celery, and a few peppercorns for three hours. Strain and you'll have liquid gold that transforms this simple soup into something transcendent. Boxed broth works, but homemade stock is the difference between good and memorable.
• •Save those dark green leek tops. They're too tough for this soup but perfect for stock. Freeze them until you have enough to make a batch, along with onion trimmings, celery leaves, and parsley stems.
• •The soup thickens considerably as it cools and even more when refrigerated. Thin reheated portions with additional stock or water until it flows properly from the spoon.
• •A tablespoon of cold butter whisked into each hot serving creates an extraordinary richness and glossy finish. This is called mounting with butter, and it's worth the extra calories.
• •For dinner parties, make this soup two days ahead. The flavors marry and improve with time. Reheat gently and finish with fresh chives just before serving.

Advance Preparation

• •The soup base without cream can be made up to 3 days ahead and refrigerated. Add cream when reheating to preserve its fresh dairy flavor.
• •Finished soup freezes beautifully for up to 3 months. Freeze in portion-sized containers for quick weeknight meals. The texture may separate slightly upon thawing but will come back together with gentle stirring over low heat.
• •For vichyssoise, prepare the complete soup 1 day ahead and refrigerate. The cold rest improves flavor. Adjust seasoning and add a squeeze of lemon before serving chilled.

Frequently Asked Questions

Nutrition Information

1 serving (about 360g)