Preheat the oven to 425 degrees, and position the oven rack in the center of the oven. Line a baking sheet with parchment paper and set aside.

Place the flour, baking powder, and salt in the bowl of a food processor. Pulse a few times just to combine. Add the cold butter and pulse about 10 times, or until the butter resembles coarse meal, with chunks of butter still visible. Pour in the buttermilk and pulse another 20 times, or until the dough comes together in large sized clumps.

Pour the dough into a large bowl and gently squeeze the dough together, just until it comes together in a ball. Be careful not to overwork the dough as it will result in tougher scones. Place the dough on a lightly floured work surface and flatten gently. Sprinkle the top of the dough with flour, and flour your rolling pin. Roll the dough to 1" in thickness. Using a 2 3/4" round biscuit cutter, cut the scones out and place on the prepared baking sheet 2" apart. Re-roll the remaining dough and cut out more scones until the dough has all been used. You will get about 8 large sized scones. Lightly coat the top of each scone with the egg wash, and bake in the preheated oven for 14-17 minutes, or until the tops are golden brown. Cool on a wire rack for 5 minutes, and serve warm or at room temperature. Enjoy!