Combine oatmeal and flour in a bowl.
Add sugar, baking powder, and salt, and mix evenly.
Cut cold butter into the mixture and blend with your hands or a pastry cutter until crumbly.
Add milk and egg, and gently knead into a dough until just combined.
Shape the dough into a round disk and cut into 6-8 wedges.
Place the scones on a parchment-lined baking sheet with space between them.
Bake in a preheated oven at 180℃ for 20-25 minutes until golden brown.