Preheat oven to 400°F (200°C). Line two baking sheets with parchment paper or a silicone liner. Alternatively, lightly grease the pans.
In a large bowl, combine the flour, sugar, baking powder, baking soda, and salt. Cut in the butter with a pastry blender or a fork until the mixture resembles coarse meal. (Alternatively, use a food processor with a metal blade to cut in the butter.)
Stir in the cinnamon and chopped apples. Do not over-work the dough.
Add 1 & 1/4 cups (300ml) of the buttermilk. Mix until combined and the dough begins to stick together. Add the remaining buttermilk if the dough is too dry.
Turn the dough out onto a lightly floured work surface. Divide the dough in half, and roll or pat each portion into a 6-inch round about 1 & 1/2 inches thick. Cut each round in half, then cut each half into 3 triangles. Place the scones on the baking sheets.
Beat together the egg and milk. Brush the tops of the scones with the egg wash. (You may not need to use all of it.) Then, sprinkle with cinnamon sugar.
Bake 25 to 30 minutes, or until golden brown and firm to the touch. Serve immediately.
Notes
Recipe slightly adapted from The Foster’s Market Cookbook.
Store scones in an airtight container at room temperature for up to 2 days.