Whisk flour, sugar, salt, and baking powder 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 as you mix the wet ingredients together.
Whisk ½ cup heavy cream, the egg, and vanilla extract together in a small bowl.
Drizzle over the flour mixture, add the add-ins, then mix together until everything appears moistened.
Pour onto the counter and, with floured hands, work dough into a ball as best you can.
Press into an 8-inch disc and, with a sharp knife or bench scraper, cut into 8 wedges.
Brush scones with remaining heavy cream and for extra crunch, sprinkle with coarse sugar.
Place scones on a plate or lined baking sheet and refrigerate for at least 15 minutes.
Preheat oven to 400°F (204°C).
Line a large baking sheet with parchment paper or silicone baking mat(s).
After refrigerating, arrange scones 2-3 inches apart on the prepared baking sheet(s).
Bake for 18-26 minutes or until golden brown around the edges and lightly browned on top.
Remove from the oven and cool for a few minutes.
