Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.

In a large mixing bowl, whisk together the all-purpose flour, granulated sugar, salt, and baking powder until well combined.

Add the cold, cubed unsalted butter to the dry mixture and rub it into the flour until it resembles coarse crumbs.

In a separate bowl, whisk together the large egg, whole milk, and vanilla extract until just blended.

Pour the wet ingredients into the dry mixture and stir gently until just combined.

Transfer the dough onto a lightly floured surface, and knead gently 4-5 times to bring it together, then roll out to about ½ inch thick.

Using a 2-inch round cutter, cut rounds from the dough and place them on the prepared baking sheet.

Bake for 12-15 minutes or until lightly golden around the edges.

Cool on a wire rack for a few minutes, then dust the tops with powdered sugar before serving.