Preheat oven to 400°.
In a mixing bowl, combine the dry ingredients: flour, sugar, baking powder and salt. Reserve some flour (about ½ a Tablespoon) for your flat workspace where you will roll the dough.
Mix in butter with a fork or pastry cutter. Keep cutting until you have smaller pieces about the size of a pea.
Whisk heavy whipping cream, 1 egg and the vanilla then add to the mixing bowl with the dry ingredients. Combine.
Shape the dough into a ball and flatten on your lightly floured surface. Cut into desired shapes, such as triangles. Place them on a baking sheet and top with blueberries.
Separate the yolk from one egg and coat the scones with the egg white wash. Freeze for about 10 minutes to chill.
Cook for 11 minutes or until golden brown on top and bottom.