In a large bowl, combine AP flour, sugar, salt, and cinnamon.

Grate your cold, nearly frozen butter into your bowl of flour and gently start to work it in with a fork. Do not use your hands, as they will melt the butter.

In a pyrex measuring cup, combine heavy cream, sour cream, egg, applesauce, and maple syrup until homogenous.

Add your liquid ingredients and your chopped diced apples to your butter and flour mix and gently work together with a fork or chopstick. Do not over-mix. Just work the dough together until it clumps and flakes together.

Gather your dough into a disk and wrap in plastic wrap. Place in the fridge to chill for 20 - 30 minutes.

Preheat oven to 400°F. Remove your scone dough from the plastic wrap and let stand on a lightly floured counter for 5 minutes. Then, lightly pat or roll into a thick disk, about 10" in diameter.

Cut out 6 triangular scones and transfer them to a parchment paper-lined baking sheet. Place in the fridge to chill while you prepare your streusel topping.

In a medium-sized bowl, combine sanding sugar, Demerara sugar, cinnamon, salt, and softened butter until it's cohesive and clumpy.

Remove your scones from the fridge and brush the tops of each with an egg wash (1 egg + 1/4 cup heavy cream). Then, sprinkle the top of each scone generously with your streusel.

Bake for 30 - 45 minutes until the scones are golden brown and lightly caramelized. Serve warm or top with an apple cider and powdered sugar glaze.