- Preheat the oven to 375°F. Lightly grease a baking sheet, or line it with parchment.
- Mix the dry ingredients in a large mixing bowl. Add the butter, working it in to make an unevenly crumbly mixture.
- Add the fruit and nuts, mixing until they're evenly distributed. Stir in the buttermilk.
- Turn the dough out onto a well-floured surface and cut it into two pieces. (Keep sprinkling on flour if you need to.) Form each into a disk, and gently pat each disk into a round about 6" in diameter.
- Transfer the disks to the prepared baking sheet, and sprinkle them with sparkling sugar, if desired, pressing it in firmly.
- With a bench scraper or sharp knife, cut the round into 8 wedges. Do this by cutting straight down through the dough so you shear the edges. If you saw the dough, you tend to press the edges together, which keeps the scones from rising as they bake. Separate the scones slightly; there should be about 1" between them at the outside edge.
- Bake the scones for 20 minutes, or until they're just beginning to brown. A toothpick inserted into the center of one should come out clean, or perhaps with a few moist crumbs clinging to it.
- Remove the scones from the oven, and serve them warm. To serve later, reheat for 10 minutes, lightly tented with foil, in a preheated 350°F oven.
- Store any leftovers at room temperature, well wrapped, for several days. Freeze for longer storage.