Mix the self-raising flour, baking powder, and sugar together.
Using your fingertips, rub the cubed butter into the dry ingredients until the mixture resembles fine breadcrumbs.
Using a wooden spoon, add the buttermilk and bring the dough together.
Turn the dough out onto a lightly floured board and gently bring it together until smooth.
Using a rolling pin, gently roll the dough into a rectangle approximately 2 inches thick.
Using a glass or cutter, cut out the scones, pressing straight down without twisting to give them the best chance of rising straight. If you twist the cutter, the scones can bake at an angle.
Place the scones on the prepared tray and brush only the tops with the egg glaze or milk.
Bake for 8–12 minutes, or until golden brown on top.
Allow to cool slightly before serving.
The scones are best enjoyed on the day they are baked, although they can still be delicious the following day if refreshed in an air fryer, microwave or toaster.
Recipe by Marissa's Recipes & Ideas at https://www.marissa.co/fionas-buttermilk-scone-recipe/