Whisk the flour, cocoa powder, sugar, baking powder, cinnamon, and salt together in a large bowl.

Grate the frozen butter using a box grater. Add it to the flour mixture and combine with a pastry cutter, two forks, or your fingers until the mixture comes together in pea-sized crumbs.

Place in the refrigerator or freezer while you mix the wet ingredients.

Whisk the heavy cream, egg, and vanilla extract together in a small bowl.

Drizzle over the flour mixture, add the 6 ounces of chopped chocolate, and then mix until everything appears moistened.

Pour the dough onto the counter and, with floured hands, work it into a ball as best you can.

Press the dough into an 8-inch disc and, with a sharp knife or bench scraper, cut into 8 wedges.

Place scones on a plate or lined baking sheet and refrigerate for at least 15 minutes and up to 1 day.

Preheat the oven to 425°F (218°C).

Line a large baking sheet with parchment paper or a silicone baking mat.

After refrigerating, arrange the scones 2-3 inches apart on the prepared baking sheet(s).

Bake for 5 minutes. Without removing the scones from the oven, reduce the oven temperature to 400°F (204°C) and continue baking for 16–17 minutes, or until the edges and tops are set.

Remove from the oven and cool for a few minutes while you prepare the glaze.

Whisk the confectioners’ sugar, vanilla, and water together.

Dip the warm scones into the glaze and place on a wire rack with a baking sheet or paper towels underneath to catch the glaze as it drips down.

Before serving, melt the remaining 4 ounces of semi-sweet chocolate in the microwave in 15 second increments, stirring after each increment until melted. Drizzle over the scones.