Ingredients (serves 4)
1 tablespoon olive oil, knob of butter, 1 large potato (peeled and chopped), 1 white onion (peeled and chopped), 400g watercress, 350ml vegetable or chicken stock, 300ml full cream milk, lemon juice, dollop of creme fraiche
Heat the olive oil and butter and sweat the onion until translucent, Add the potato and cook for 4 minutes, without allowing it to brown. Add the stock and simmer until the potato is tender. Roughly chop the watercress and add to the pan. Take off the heat and allow to cool slightly, before transferring to a food processor to blend until smooth.
Transfer back to the saucepan and add the milk to create a creamy consistency. Bring to simmering point and then remove from the heat. Add a little lemon juice and season to taste.
Serve with a dollop of creme fraiche and some leftover sprigs of watercress.