Preheat oven to 375 degrees F. Combine currants and water in Pyrex measuring cup. Microwave to boiling point, cover, and let stand.
Combine first 5 dry ingredients in large mixing bowl or Cuisinart bowl. Cut in butter with pastry knife, or pulse in Cuisinart until it resembles coarse meal. Drain currants, then add to mixture with oatmeal. Stir in buttermilk until dough is barely moistened.
Turn dough onto floured board and knead 6 to 8 times. Roll or pat into a circle, place on ungreased baking sheet, and score into 8 wedges. Brush the top with melted butter and sprinkle with coarse-grained sugar. Bake for about 15 minutes.
This recipe can be doubled and divided into 3 circles with 6 wedges each. Doubled it yields about 30 two-inch round scones.