Ingredients
4½ cups all-purpose flour
½ cup sugar
2 teaspoons baking powder
½ teaspoon baking soda
½ teaspoon salt
¾ pound (3 sticks) cold unsalted butter, cut into ¼-inch pieces
1¼ cups plus 2 tablespoons buttermilk
Egg wash: 1 large egg beaten with 2 tablespoons milk
Instructions
1. Preheat the oven to 400 degrees.
2. Lightly grease 2 baking sheets and set aside.
3. Combine the flour, sugar, baking powder, baking soda, and salt in a large bowl.
4. Add the butter and cut it into the flour mixture using a pastry blender or 2 knives until the mixture resembles coarse meal. (Or use a food processor fitted with the metal blade to cut the butter into the flour mixture by pulsing 10 to 12 times. Transfer the mixture to a large bowl to continue making the dough.) Do not overwork the dough.
5. Add 1¼ cups of the buttermilk and mix until just combined and the dough begins to stick together. Add the remaining buttermilk one tablespoon at a time if the dough is too dry.
6. Turn the dough out onto a lightly floured surface and roll or pat into two 6-inch rounds, about 1½ inches thick. Cut each round in half, then cut each half into 3 triangles (pie-shaped wedges) and place on the baking sheets. Brush the tops with the egg wash.
7. Bake 30 to 35 minutes, until golden brown and firm to touch. Remove from the oven and serve immediately.
