Whisk flour, 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 until the mixture comes together in pea-sized crumbs. Place in the refrigerator or freezer as you mix the wet ingredients together.

Whisk 1/2 cup heavy cream, the egg, and vanilla extract together in a small bowl. Drizzle over the flour mixture, add the blueberries, then mix together just until everything is moistened.

Pour onto the counter and, with floured hands, work dough into a ball as best you can. Dough will be sticky. Press into an 8-inch disc and, with a sharp knife or bench scraper, cut into 8 wedges.

Place scones on a plate and refrigerate for at least 15 minutes. Preheat oven to 400°F.

Brush scones with heavy cream and sprinkle with coarse sugar. (Sugar is optional.)

Move scones to a lined baking sheet. Bake at 400°F for 22-25 minutes. The edges should be golden brown and the top lightly brown. Move to a wire rack to cool.

Optional: Whisk icing ingredients together to make icing and drizzle over scones as desired. Add the cream a little at a time until it’s thin to your liking.