Leek, Watercress and Blue Cheese Vichysoisse

• 1 onion, chopped
• 3 leeks, chopped
• 50 g (2

This is one of my favourite chilled soups. The cheese adds a little tanginess which blends well with the leek and peppery watercress.

Sweat the onion and leeks in the butter for about 5 minutes, until beginning to wilt. Add the potatoes and cook for 5 minutes longer. Add the stock and bring to the boil, then reduce the heat to a simmer and cook for 25 minutes, until all the vegetables a