Ingredients
- 750 g (1 lb 10 oz) asparagus spears
- 1 litre (35 fl oz/4 cups) vegetable stock
- 30 g (1 oz) butter
- 1 tablespoon plain (all-purpose) flour
- 1/2 teaspoon finely grated lemon zest, plus extra, to garnish
Method
1. Trim off any woody ends from the asparagus and cut the spears into 2 cm (3/4 inch) lengths. Place in a large saucepan and pour in 500 ml (17 fl oz/2 cups) of the stock. Cover and bring to the boil, then reduce the heat and simmer for 10 minutes, or until the asparagus is tender.
2. Working in batches, transfer the asparagus and the hot stock to a blender or food processor and purée until smooth. Set aside.
3. Wipe out the saucepan, then add the butter and melt over low heat. Add the flour and stir for 1 minute, or until pale and foaming. Remove from the heat and gradually add all the remaining stock, stirring constantly until smooth.
4. Return the saucepan to the heat, bring to the boil, then simmer for 2 minutes.
5. Stir in the asparagus purée and gently reheat. Stir in the lemon zest and season to taste with sea salt and freshly ground black pepper. Serve garnished with a little extra lemon zest.
