Cook the washed berries in water and sugar until soft (about 5 to 10 minutes, depending on the kind of berries and degree of ripeness).
If you use frozen berries, mix the thawed fruit with 1/2 cup sugar (do not cook).
Sift together flour, baking powder, and salt.
Pinch in the butter with your finger tips until well dispersed, then stir in enough milk to make a soft dough.
Place berries in bottom of a 1 1/2 quart mold or ovenproof bowl, spoon dough on top, and cover tightly with a lid or a piece of foil.
Place in a deep kettle and pour in enough boiling water to reach the halfway mark.
Cover the kettle and simmer slowly for 1 1/2 hours.
Turn out of mold and serve hot with cream or New England Nutmeg Sauce.