Delia Smith’s leek and potato soup sweats leeks, onion and potato in butter, then simmers them in vegetable stock and milk before blending to a smooth purée. It’s finished with a swirl of cream and a scatter of chives. There’s no cream cooked into the body, which keeps it light. It serves four to six and takes about 35 minutes.
She calls it Leek, Onion and Potato Soup in The Delia Collection: Soup, and it’s one of her own favourites. What sets it apart is that she builds it on milk and vegetable stock rather than cream, so it stays light and fully vegetarian. The cream comes in only as a swirl at the end, so you get richness without heaviness.
The one thing to watch is the heat once the milk goes in. Delia warns that if the pan is too hot, the milk will make the soup boil over. A milk-based soup needs a gentle simmer, not a hard boil, or it climbs the pan and can catch or split. Keep it low and let it tick over quietly.
Delia Smith Leek And Potato Soup
Course: Soups, DinnerCuisine: BritishDifficulty: Easy4-6
servings15
minutes35
minutes215
kcal50
minutesFrom The Delia Collection: Soup and Delia’s Vegetarian Collection. A light, vegetarian blend built on milk rather than cream, with cream saved for a swirl on top. Doubles as chilled vichyssoise.
Ingredients
4 large leeks
1 medium onion, chopped small
2 medium potatoes, peeled and diced
50g butter
850ml vegetable stock
275ml milk
salt and freshly milled black pepper
- To serve:
2 tablespoons cream or crème fraîche
1½ tablespoons snipped fresh chives or chopped fresh parsley
Directions
- Prep the leeks: Trim the leeks and discard the tough outer layer. Split them in half lengthways, slice quite finely, then wash thoroughly in two or three changes of water and drain well.
- Sweat the vegetables: In a large, thick-based saucepan, gently melt the butter. Add the leeks, onion and potatoes and stir to coat them in the butter. Season with salt and pepper, cover, and let them sweat over a very low heat for about 15 minutes.
- Simmer: Add the stock and milk and bring to simmering point. Cover and simmer very gently for a further 20 minutes, until the vegetables are soft. Keep the heat low so the milk doesn’t boil over.
- Blend: Let the soup cool a little, then blend to a smooth purée, in batches if needed.
- Finish: Return the soup to the pan and reheat gently, tasting to check the seasoning. Serve with a swirl of cream or crème fraîche and a sprinkle of chives or parsley.
FAQs
Can I serve this cold as vichyssoise?
Yes, and Delia points this out herself: chilled, this soup becomes a classic vichyssoise. Make it exactly as written, let it cool, then chill it thoroughly before serving. Cold blunts seasoning, so taste and adjust the salt before it goes to the table, and give it an extra swirl of cream.
Why does Delia use milk instead of cream in the soup?
Building the body on milk keeps the soup light and lets the leek flavour come through, rather than smothering it in cream. It also keeps it economical and fully vegetarian. If you want it richer you can swap some of the milk for cream, but you’ll lose the fresh, clean edge that makes Delia’s version so easy to eat a bowl of.
How is Delia’s leek and potato soup different from Mary Berry’s?
They take different routes to the same comfort. Delia keeps hers light with milk, vegetable stock and cream only on top, while Mary Berry’s leek and potato soup enriches the body with single cream and adds nutmeg and a squeeze of lemon. Delia’s is the lighter, purer bowl; Berry’s is warmer and more seasoned.
Why wash the leeks so thoroughly?
Grit and soil hide between the tightly packed layers of a leek, especially near the top. Slicing them first and then washing in two or three changes of water flushes out that grit far better than rinsing them whole. Skip this and you risk a gritty soup, which no amount of blending will fix.
Do I have to blend it, or can I leave it chunky?
Delia blends hers to a smooth purée, which is the classic finish and what makes it silky. If you prefer texture, blend only half and stir it back into the chunky half for a rustic version. Either way, let it cool a little before blending so hot soup doesn’t blow the lid off the blender.
Can I make it ahead or freeze it?
It keeps well in the fridge for a couple of days and reheats gently, which suits making it the day before. Freezing is possible, though the milk can turn slightly grainy once thawed, so stir it well as it reheats. Always hold the cream swirl back until serving rather than freezing it in.
