~from Savoring Time in the Kitchen
3-1/3 cup all purpose unbleached white flour
2 scant Tablespoons sugar
1 Tablespoon baking powder
1-1/4 teaspoons salt
11 Tablespoons (1 stick, plus 3 Tablespoons) butter, frozen until firm
1-1/8 cup buttermilk
Finely grated zest of one lemon
1 egg, beaten, for glazing
A very sharp knife is necessary to as not to depress the dough when cutting into triangles for baking. Otherwise, they will not rise properly.
Preheat oven to 400 ° F.
In a small bowl, mix together buttermilk and lemon zest. Refrigerate until needed.
In a large bowl, whisk together flour, baking powder, salt and sugar.
Remove the butter from the freezer and, using a box grater, grate the butter quickly and coarsely onto a piece of parchment or waxed paper. Refreeze briefly, if it has become soft again, then add the butter to the flour mixture and blend the butter into the flour with a fork or pastry cutter.
Add the buttermilk mixture to the flour/butter mixture and mix together until the ingredients are just barely blended together. Do not over-mix.
Flour a work surface and turn out the dough. Using your hands, gently flatten it to form a rectangle.
With a rolling pin, roll out dough to half an inch thick, keeping the rectangular shape. Fold dough in half and rotate 90 degrees and repeat these last two steps twice again.
Roll the dough one last time to obtain a rectangle of 18 "x 9".
Taking the shorter ends, make an 'envelope fold', folding one short end to the center and then the other short end over that fold (into thirds). You now have a 6 "x 9" rectangle.
Using a VERY sharp knife or dough cutter, cut a thin layer of dough on each side of your rectangle. This step will make those nice layers during cooking.
Cut 6 square 3" x 3" scones...then cut each square in half on the diagonal to form triangles.
Place on a baking sheet lined with parchment paper spaced three inches apart. Brush lightly with egg wash.
Bake for 20 to 22 minutes or until light golden brown.
Adapted from this recipe.