Preheat Oven: Preheat your oven to 400°F. Line a baking sheet with parchment paper; set aside.
Combine Dry Ingredients: In a large bowl combine the flour, sugar, baking powder and salt. Grate the butter using a box grater then add it to the flour mixture and mix it in.
Mix Wet & Dry Ingredients: In a medium bowl, combine the egg, heavy cream, sour cream and vanilla. Make a well in the center of the flour mixture and add the wet ingredients. Using a fork, stir until moistened.
Knead Dough: Turn the dough onto a lightly floured and clean work surface. Gently knead the dough about 10 to 12 times and form it into a bowl. If dough is too sticky, add a bit more flour.
Divide & Cut Dough: Divide the dough in half. Roll out each half into a 6-inch circle. Using a pizza cutter or sharp knife, cut into 6 wedges, just like you'd cut a pizza. Place these wedges onto the prepared baking sheet, 2 inches apart. Repeat with remaining dough.
Finish Rolls: Brush the rolls with additional heavy cream, then sprinkle with coarse sugar.
Bake & Cool: Transfer the baking sheet to the oven and bake for 12 to 14 minutes or until bottoms are golden. Remove the scones from the baking sheet and finish cooling on a wire rack.