In a large bowl, whisk together the flour, baking powder, cinnamon, and salt.
Grate the frozen butter and add it to the flour mixture. Use a pastry cutter or your fingers to blend until it resembles pea-sized crumbs. Chill this mixture while preparing the wet ingredients.
In a separate bowl, whisk together the heavy cream, brown sugar, egg, and vanilla extract.
Pour the wet ingredients over the dry ingredients, add the chocolate chips, and stir until just moistened.
Turn the dough out onto a floured surface and shape into a ball. Flatten into an 8-inch disc and cut into 8 wedges.
Place the scones on a plate, brush with extra heavy cream, and sprinkle with coarse sugar if using. Refrigerate for at least 15 minutes.
Set the oven to 400°F and prepare a baking sheet with parchment paper.
Arrange the chilled scones on the baking sheet and bake for 22-25 minutes until golden brown. Sprinkle with confectioners' sugar, if using. Let cool slightly before serving.