Preheat oven to 425° F / 220° C. Line a half-sheet rimmed tray with a silicone mat.

In a large bowl, whisk together self rising flour and baking powder.

Add the butter and use your fingertips to combine, rubbing the mixture together until it resembles coarse breadcrumbs. Stir in the granulated sugar.

Form a well in the dry ingredients. Pour in the milk.

With a bench scraper, work the milk into the dry ingredients until a shaggy dough forms. Do not overmix.

Tip out onto a lightly floured work surface. With floured hands, bring dough together until a ball forms. Do not overwork. You should still see some strands and small pieces of butter in the dough.

Flatten into a disc, about 7 inches in diameter and 1 inch thick.

With a floured 2-inch (4-5 cm) round cutter, cut the dough into rounds.  Transfer to prepared tray.

Reshape scraps into a 2-inch thick disc and cut remaining rounds. You should have about 12 total.

With a pastry brush, brush the tops of the scones with the beaten egg.

Bake in preheated oven for 15-18 minutes or until risen and lightly golden brown.

With a flat metal spatula, transfer scones to a wire rack. Allow to cool completely, or serve while still slightly warm.

Store leftover scones in an airtight container at room temperature for up to 3 days, or layer between sheets of parchment and freeze in an airtight container for up to 3 months.