Leek and Potato Soup

Ingredients:

20z / 50g butter
1 lb / 450g potatoes, peeled and cut into 1/2" / 1cm pieces
1 small onion, cut the same size as the potatoes
1 lb / 450g white parts of leeks, sliced (save some the green tops for garnish)
2 pts / 1.2 litres vegetable stock
5 floz / 150ml thick cream (double or whipping)
4 floz / 125ml full-fat milk
Salt & ground black pepper

Method:

Melt butter in a heavy saucepan; add potatoes, onion, and white parts of leeks, sliced and toss them in the butter until they are well coated. (keep a little leek to garnish)
Season well with salt and freshly ground pepper and toss again, then cover the pan with its lid
Cook over a gentle heat for 10 minutes, or until the vegetables are soft but not coloured
Uncover the pan and discard the paper. Pour in the vegetable stock, bring to the boil and simmer until the vegetables are just cooked – about 5 minutes. Do not overcook or the soup will lose its fresh flavour
Purée in a blender until silky smooth, in batches if necessary, then taste and adjust the seasoning. Return the soup to a clean pan and stir in 3/4 of the cream and the milk
To finish the soup, finely shred the remaining white leek and some of the green leek; gently cook it in a small knob of hot butter for a few minutes until it is softened but not coloured
Pour into warmed bowls, drizzle the remaining cream over each serving, top with a little pile of buttered leeks and serve at once