Melt
butter in a large pan. Saute onion and celery for
about 5 minutes until softened. Add flout and curry
powder and continue cooking for 3 minutes, stirring
occasionally to prevent sticking.
Stir
in apple, chicken and 1 cup of stock. Simmer for
about 5 minutes. Cool slightly.
Puree mixture in a food processor or blender. This
may need to be done in several batches. Return puree
to pan. Add the remaining chicken stock, lemon juice
and seasonings.
Bring to a boil. Simmer for about 10 minutes, cool
and chill in refrigerator. Serve cold with a
spoonful or yogurt or whipping cream in each bowl
and a sprinkling of chopped chives.