In a large bowl, whisk together all-purpose flour, rolled oats, sugar, baking powder, baking soda, cinnamon and salt. Using pastry blender, cut in butter until crumbly.
In separate bowl, whisk buttermilk with egg; pour over flour mixture. Stir with fork to make ragged dough.
With lightly floured hands, press dough into ball. On floured surface, knead gently 10 times. Place on parchment paper-lined baking sheet. Pat into 1/2-inch thick round. Cut into 8 wedges.
Topping: Brush dough with buttermilk: sprinkle with sugar. Bake in 400 degree oven until golden, about 25 minutes. Transfer to rack; let cool.
Store in airtight container for up to 24 hours or wrap in plastic wrap and freeze in airtight container for up to 2 weeks.
Go to full version of