Mushroom and Pearl Barley Soup

This soup from the Slavic countries used to be a delicacy for poor people and gypsies. I like the idea of these humble ingredients being brought together to produce a simple dish. The original recipe used double cream, but I have substituted thick soured cream to give another dimension. If you cannot find soured cream, then use thick double cream mixed with a little lemon juice. Serve with toasted bread.