Line a baking sheet with parchment paper or a silicone baking mat.
Preheat oven to 425 F.
Sift dry ingredients (flour, baking powder, baking soda, cinnamon, sugar) into a large mixing bowl. Stir together.
Cut cold butter into 1/2 inch cubes.
Use a pastry cutter to cut the cold cubed butter into the flour mixture. Cut until butter pieces are no larger than the size of small peas. Don't overdo it. You want to leave some small chunks of butter. The steam created by the melting butter chunks will create the flaky layers in your scone. If you don't have a pastry cutter, you can use two sharp knives, or pulse carefully in the food processor.
Add wet ingredients (milk and grated apples) to the flour-butter mixture and stir gently with a fork to combine. You should have a sticky, shaggy dough.
Turn the dough out onto a well floured surface and knead 3-4 times.
Divide dough into two balls. Flatten each ball into a circle, roughly six inches in diameter.
Place the circles of dough onto the prepared baking sheet. Use a sharp knife to cut each circle into six pieces.
Place scones in refrigerator or freezer for 15 minutes to chill.
While the scones chill, combine the egg yolk and heavy cream in a small bowl to make the egg wash. Remove scones from refrigerator and use a pastry brush to gently brush tops of the scones with egg wash.
Sprinkle tops of scones with sanding sugar.
Place scones in hot oven and bake for 15-20 minutes until golden brown. Enjoy the smell of apples and warm spices wafting from your oven.
Remove from oven and let cool for 5 minutes on the baking sheet, then remove to a wire rack to fully cool.