‘Four Seasons’ Watercress Vichyssoise

• 5 potatoes, peeled and sliced
• 2 large leeks, sliced
• 1½ bunches watercress

Cook sliced vegetables with ham bone in stock until done. Put through a blender or purée through a fine sieve. Season with salt and pepper, and chill. Just before serving, add chilled cream. Serve with watercress.