Grate your very cold (or frozen) butter and grind your wheat berries.
Then, mix the dry ingredients. In a large bowl, whisk together the whole wheat flour, baking powder, salt, and sugar.
Next, using a pastry cutter or your fingers, work the butter in to the flour until the mixture resembles coarse crumbs.
In a seperate bowl, whisk your sourdough starter, 1 egg, vanilla extract, and milk until smooth.
Add the wet ingredients to the dry ingredients until the dough just comes together. Don't overwork it. The dough will be a little sticky.
Gently fold in your mix ins.
Turn the dough out onto a lightly floured surface and gently pat it into a disc that's about 8 inches. I like to dump it directly onto plastic wrap. Wrap it securely and place into the fridge overnight.
The next morning, preheat your oven to 400 degrees. Take your dough out of the fridge and using a bench scraper cut the disk into 8 triangles. Lightly beat an egg and brush it over the tops of the scones.
Transfer the scones to a piece of parchement paper on a baking sheet and bake in the preheated oven for 20-25 minutes or until they're golden brown. Let cool for a few minutes on a wire rack. Serve warm and enjoy!