In a 6-qt. kettle, combine the blackberries, sugar, water and butter; bring to a boil.
For dumplings, combine the flour, baking powder, sugar and salt. In a large bowl, beat egg and milk; stir in dry ingredients until a soft dough forms. Drop by tablespoonfuls onto boiling berry mixture. Reduce heat; cover and simmer for 15-20 minutes or until dumplings test done (do not lift the cover while simmering).
Serve warm with cream if desired.
Editor's Note: Raspberries may be substituted for the blackberries.