Creamy Leek Soup

This is the British classical method for a smooth leek soup: two pots, one for the leeks and stock, one for a bechamel built from butter, flour, milk, and single cream. They come together at the end and get pureed into something silkier than a typical blended cream soup.

Why two pots? Because cooking the flour in butter first (a roux) and slowly adding cold dairy prevents the lumps that form when you dump flour into hot stock. The bechamel also adds a velvety mouthfeel that thickens the soup without diluting the sweet, oniony flavor of the leeks themselves.

The gentle 5-minute saute of leeks and onion at the start matters. You want them sweated and soft, not browned. Browning shifts the flavor into a darker, more caramelized profile that fights with the clean cream finish you’re aiming for.

Chef Tips

• Wash leeks thoroughly. Slit lengthwise and rinse between the layers. Grit hides deep in the green parts.
• Use only the white and pale green sections for the cleanest flavor. Save the dark greens for stock.
• Reheat gently after pureeing. Boiling cream-based soups can cause them to separate.
• For an even silkier finish, pass the pureed soup through a fine-mesh sieve.

Variations

• Stir in 100g of grated sharp cheddar at the end for a leek and cheese soup.
• Add a peeled and diced potato with the stock for a more substantial leek and potato soup (vichyssoise-style chilled or hot).
• Garnish with crispy bacon bits, snipped chives, or a swirl of truffle oil for a fancier presentation.