Potato and Leek Soup
To make potato and leek soup, slice the leeks and rinse them well to remove grit, then soften them gently in butter without browning. Add diced potatoes and stock, simmer until the potatoes are tender, about 20 minutes, then blend until silky. Season with salt and pepper and finish with a little cream. Cooking the leeks slowly and softly is the key to a sweet, mellow flavour. Serve hot with chives, or chilled as vichyssoise.
When the first genuinely cold evening arrives, potato and leek soup is the pot to put on. It’s built from the humblest, cheapest ingredients — leeks, potatoes, butter, stock — and turns them into something silky, comforting, and quietly elegant. It’s also endlessly forgiving and freezes beautifully.
Wash those leeks
Leeks grow with soil packed between their layers, so a proper clean matters. Slice them first, then swish the slices in a big bowl of cold water and lift them out — the grit sinks to the bottom and stays there. Running them under the tap just pushes the sand deeper. Use the white and pale-green parts; the tough dark tops are great saved for stock.
Sweat, don’t brown
The whole character of this soup comes from cooking the leeks gently — “sweating” them in butter over low-medium heat until soft, sweet, and silky, with no colour. Browning adds a bitter edge that muddies the clean, delicate flavour you’re after. Low and slow, stirring now and then.
Blend to silk
Once the potatoes are meltingly tender, blend everything smooth. Starchy potatoes give the soup its velvety body — no cream even required, though a little at the end makes it luxurious. Season with white pepper to keep the colour pale and pretty.
Make it yours
- Vichyssoise: chill it and serve cold with extra cream and chives — the classic French version.
- Loaded: top with crispy bacon, grated cheddar, and croutons.
- Greener: stir in a handful of spinach or watercress before blending.
- Lighter: skip the cream; the potato carries it.
Serve hot with a swirl of cream and a shower of chives, and good bread for dipping. Make a double batch — a jar of this in the freezer is the easiest cold-weather lunch there is.
Frequently asked questions
How do I clean leeks properly?
Leeks trap grit and sand between their layers, so they need a good wash. Slice them first, then swish the slices in a bowl of cold water and lift them out, leaving the sand behind at the bottom — don't just run them under the tap, which traps the grit. Use the white and pale-green parts; save the tough dark-green tops for stock.
Why shouldn't I brown the leeks?
For this soup you want the leeks sweet and mellow, not caramelized, so cook them gently in butter over low-medium heat until soft and silky — 'sweating' them. Browning adds a bitter, savoury edge that muddies the clean, delicate flavour. Keep the heat low and stir; if they start to colour, turn it down.
Can I make it ahead or freeze it?
Yes to make-ahead — it keeps 3–4 days and the flavour deepens. Freezing works best before adding cream (dairy can separate on thawing); freeze the blended potato-leek base, then reheat and stir in cream fresh. Served chilled with cream, this same soup becomes classic vichyssoise.