In a bowl, mix the softened butter and the sugar. Add flour and baking powder and evaporated milk. (Until "used" as Grandmama used to say/ or til' you cain't tell one ingredient from another.)Put the blueberries in a pot and add water enough to cover the berries and the 1/2 cup of sugar. Give it a stir and bring it to a boil and cook for only about 2 minutes. Pour blueberry mixture into a baking or pyrex dish and pour the flour mixture over the top of the blueberries. Yes, some of it will sink. But, don't worry. Bake for about 30 minutes at 350 til the top is golden brown. Serve with a some vanilla ice cream or whipped cream. YUM!