For the scones, cut the butter into small cubes. Transfer to a small bowl and keep in the fridge.
In a large mixing bowl, combine flour, baking powder, cinnamon and salt. Add the butter cubes and combine with a pastry cutter, a fork or your fingers until there are no pieces of butter larger than a pea. Keep in the fridge to chill.
Line a large dinner plate with a piece of wax paper. Set aside.
In a medium bowl, whisk together heavy cream, egg, light brown sugar and vanilla extract. Pour the wet ingredients into the flour mixture. Using a spatula, stir until the flour is moistened. Add apple and mix well. The dough will be sticky and wet.
On a clean work surface, lightly dust with flour. Scoop the dough onto the work surface. Cover your hands with flour. Lightly knead dough until it just comes together (just a few seconds). Shape the dough into a 1-inch thick round disk, about 7-inch in diameter. With a sharp knife, divide the dough into 8 wedges. Transfer to the prepared dinner plate and freeze for 30 minutes.
Preheat oven to 400˚F (200˚C). Line a baking sheet with parchment paper.
Quickly brush the top of the scones with heavy cream, sprinkle generously with raw sugar. Set onto the prepared baking sheet, leaving 2 – 3 inches space between scones.
Bake in the oven for 23 – 25 minutes or until golden brown around the edges and lightly browned on top. Remove from oven and cool on the baking sheet for a few minutes.
Meanwhile, prepare the glaze if using. In a small microwave-safe bowl, add butter and milk. Microwave for 30 seconds. Add brown sugar, salt and vanilla extract. Whisk to melt the sugar. Add powdered sugar and whisk until smooth.
When ready to serve, drizzle the glaze over the scones. Serve warm.