Blueberry scones

Makes

With the rack in the highest position, preheat the oven to 425F. Line two baking sheets with parchment paper.
In a food processor, combine the flour, sugar, baking powder, baking soda and salt. Add the butter and pulse for a few seconds at a time until the mixture forms coarse, pea-sized crumbs. Add 1 cup buttermilk, and pulse until just blended.
On a floured work surface, turn out the dough. With a rolling pin or your hands, roll out the dough into a 16-inch square. Arrange the blueberries over the dough. Roll the dough into a long cylinder and press it flat to a thickness of about 1 1/4 inches while keeping it 16 inches long. Cut the dough into 7 rectangles, then cut each rectangle diagonally into triangles. Place on the baking sheets or freeze at this point.
Brush the scones with the remaining buttermilk and sprinkle with the coarse sugar.
Bake, one sheet at a time, for about 18 minutes, or until the scones are golden brown. Let cool.
Serve with orange crème fraîche if desired.