Line a baking sheet with parchment paper, and set aside.

In a large mixing bowl, combine the dry ingredients, flour through sugar. Cut the cubed butter into the flour mixture either with a pastry cutter or your fingers.

In a liquid measuring cup or small mixing bowl, combine the heavy cream, vanilla extract and egg. Whisk together. Pour into the flour mixture, and stir with a fork until combined. Gently add the blueberries.

Lightly dust your work surface with flour, and sprinkle some flour over the dough if needed. Transfer dough to your floured work surface. It will be sticky, add just enough flour to be able to pat it into a 1 inch tall circle. Cut into 8 wedges. Set each wedge onto the prepared baking sheet.

Transfer scones to the fridge, and let chill for 30-60 minutes, or covered overnight. Heat the oven to 400 degrees F while the scones chill. Just before baking, brush the extra heavy cream over each scone, and sprinkle with coarse sprinkling sugar.

Bake for 18-22 minutes, or until the scones are golden brown at the edges and on the tops.