01 - Preheat the oven to 400°F. Line a baking sheet with parchment paper.
02 - In a large bowl, whisk together the all-purpose flour, whole wheat flour, sugar, baking soda, baking powder, and salt until well blended.
03 - Add the cold butter cubes to the flour mixture. Using a pastry cutter or your fingertips, work the butter into the flour until the mixture resembles coarse crumbs with some pea-sized pieces remaining.
04 - Stir in the raisins or currants and caraway seeds if using until evenly distributed throughout the flour mixture.
05 - In a small bowl, whisk together the buttermilk and egg until combined. Pour into the dry mixture and stir gently with a wooden spoon or spatula just until the dough comes together. Do not overmix; the dough will appear shaggy.
06 - Turn the dough onto a lightly floured surface. Gently pat it into a round disk about 1 inch thick. Using a sharp knife, cut the disk into 8 equal wedges and transfer them to the prepared baking sheet, spacing them about 2 inches apart.
07 - Brush the tops of each scone with the additional buttermilk using a pastry brush. Sprinkle with coarse sugar if desired for a crunchy topping.
08 - Bake for 16 to 18 minutes, or until the scones are golden brown on top and a toothpick inserted into the center comes out clean.
09 - Let the scones cool on the baking sheet for 5 minutes before transferring to a wire rack. Serve warm with butter and jam, or with clotted cream and Irish cheddar.