Preheat your oven to 425°F (220°C). Line a baking sheet with parchment paper.

In a large bowl, whisk together the flour, baking powder, salt, and sugar.

Cut in the cold butter using a pastry blender or your fingertips until the mixture resembles coarse crumbs. Work quickly to prevent the butter from melting.

In a separate small bowl, lightly whisk together the egg and 2/3 cup of milk.

Gradually add the wet ingredients to the dry ingredients, mixing gently with a fork until just combined. Do not overmix; a few lumps are okay.

Turn the dough out onto a lightly floured surface and gently pat it into a 1-inch thick circle.

Use a 2-inch round cookie cutter or a sharp knife to cut out scones. Reroll the scraps to make more scones.

Place the scones onto the prepared baking sheet. Brush the tops with the extra tablespoon of milk (optional) and sprinkle with coarse sugar (optional).

Bake for 12-15 minutes, or until the scones are golden brown.

Let the scones cool on a wire rack before serving.