Preheat the oven to 400 F. Line a large baking sheet with parchment paper and set aside.
In a large bowl whisk the flour with the granulated sugar, salt, baking powder, and baking soda. Add the cold diced butter and work it in with your fingers, forks, or a pastry blender until the mixture resembles crumbs with some crumbs the size of peas.
Combine the buttermilk and vanilla and drizzle over the flour mixture. Stir just until the ingredients are moistened.
Turn the mixture out onto a lightly floured surface and knead a few times just until a soft dough forms.
Pat the dough into 2 circles or a large square around 1/2 to 3/4-inch thick; slice into wedges or squares.
Arrange the unbaked scones onto the prepared baking sheet. Brush with the heavy cream and sprinkle with coarse sugar.
Bake the scones for 15 to 17 minutes, until lightly browned.