Step 1

Preheat the oven to 400°F. Line a large baking sheet with parchment paper.

Step 2

In a large bowl, combine the sugar and lemon zest. Massage the mixture with your fingers to infuse the sugar with the lemon oils until the sugar color is light yellow. Stir in the flour, baking powder, salt, and baking soda. Using a pastry cutter or fork, cut in the cold butter until the pieces are no larger than the size of peas.

Step 3

In a small bowl, whisk together ½ cup of buttermilk, the egg, and vanilla. Add the buttermilk mixture to the flour mixture, and stir together using a fork or spatula until a shaggy dough forms.

Step 4

Turn out the dough onto a lightly floured surface and knead once or twice to bring the dough together. Press the dough into a 7½-inch round (about ¾-inch thick) disc.

Step 5

Using a floured knife, cut the disc into 8 equal triangles and place them on the prepared baking sheet about 2 inches apart. Brush the top of each scone with the remaining 1 tablespoon of buttermilk.

Step 6

Bake for 20 to 25 minutes or until puffed, and the tops are lightly golden, rotating the pan halfway through baking. Cool the scones on the pan on a wire rack for 20 minutes.

Step 7

In a small bowl, whisk together the powdered sugar, lemon juice, and salt until smooth. Drizzle glaze over warm scones before serving.