- 2 leeks, diced
- 75g unsalted butter
- 2 sticks celery, finely diced
- 4 cloves garlic, sliced
- ¼ bunch thyme, finely chopped
- 2 bay leaves
- 2 Tbsp plain flour
- 2L chicken stock
- 1.5kg potatoes
- salt flakes and freshly-milled black pepper
- snipped chives and sour cream, to serve
1 Sauté the leeks in half the butter in a large saucepan over a moderate heat for 5 minutes, until softened, then scoop out half the leeks and set aside. Add the celery, garlic, thyme and bay leaves to the saucepan and cook for another 5 minutes.
2 Sprinkle the flour over and cook for 2 minutes, stirring constantly, until the mixture begins to stick to the bottom, then pour in the stock.
3 Cut 1cm cubes from ? of the potatoes and reserve these. Chop the remaining potatoes and add to the saucepan with the trimmings. Simmer for 30 minutes, until the potato is tender, then season with salt and pepper and purée until smooth.
4 Steam the diced potatoes over a saucepan of simmering water until tender, then fold into the soup. Serve with snipped chives and sour cream.