Hot Cucumber Soup

• 1 small cucumber, peeled
• 1 medium-sized potato, peeled
• 4-5 spring onions

Grate the potato and cucumber coarsely; strain off the liquid that forms and put the vegetables to sweat with the finely chopped onions in enough butter to cover the bottom of a medium saucepan. Heat the stock to simmering point and add to the vegetables. Simmer gently for 20-25 minutes. Check seasoning and serve with a knob of butter in each bowl.