Put the sugar, salt and water in a large saucepan, bring to the boil and
add the apples, breadcrumbs, cinnamon and lemon rind. Simmer for 10
minutes, stirring occasionally, until the apples are soft. Remove the
cinnamon and lemon rind and puree the apple mixture in a food processor or
blender. Return the mixture to the pan, add the lemon juice, wine and
redcurrant jelly and simmer gently, stirring, until the jelly dissolves
and the soup is warmed through. Ladle the soup into warm soup bowls, add a
swirl of yoghurt to each one and serve.