Heat oven to 400 degrees and move rack to the lower middle position.
In a mixing bowl, mix flour, 1/3 cup sugar, baking powder, baking soda and salt. Then grate the frozen butter into the flour mixture on the large holes of a box grater. Work the butter into the flour until it becomes like course meal. You can also do this step in the food processor.
In a second bowl, whisk Greek yogurt, the egg, and vanilla extract until the mixture is uniform.
Using a fork, stir the Greek yogurt mixture into flour mixture until large dough clumps form. Then use your hands to press the dough into a ball. (There may not seem to be enough moisture at first, but as you work the dough it will come together.)
Turn out the dough onto a lightly floured surface and pat it into an 8-inch circle about 3/4-inch thick. Use a sharp knife to cut into 8 triangles. Place the triangles on a cookie sheet lined with parchment paper about an inch apart. Bake until golden, about 15 to 17 minutes.
By all means eat them now while they are hot! But if you are feeling really decadent, allow them to come to room temperature before frosting them with Vanilla Bean Buttercream Frosting.
Note: If you are planning to frost your scones - of course you are! - The frosting comes together quickly while the scones are baking. Just add the cream cheeese, butter, vanilla, maple syrup, the seeds from the vanilla beans, and a pinch of salt to your stand mixer (or a bowl and whisk by hand) and whisk it until it is whipped and the consistency you want it to be! If you frost the scones while they are still warm, keep in mind there are no processed ingredients in this frosting so it will melt and get all drippy and runny down the scones... Oh wait. I think I need to sit down...