For best results, keep the butter and buttermilk very cold until ready to use.
If you don't have a food processor, use a pastry cutter or two knives to cut the butter into the flour.
Scones are best served fresh but can be stored in an airtight container at room temperature for up to 2 days.
To freeze, bake, cool completely, then wrap individually and freeze for up to 1 month. Reheat in a warm oven before serving.
Substitute raisins or dried cranberries for the currants if desired.