Line a large baking sheet with a silicone mat or parchment paper. Set aside.
Place pastry cutter into the fridge.
Using very cold butter, cube the butter into small cubes. Set in the fridge.
Sift the dry ingredients: 2 1/4 c flour; 1/4 c sugar; 1/4 tsp salt; 1 Tbsp baking powder into large bowl. Set in fridge.
Whisk together the wet ingredients: 1 large egg; 2 tsp vanilla; 1/2 c yogurt; 1/4 c milk. Set aside.
Take out the butter and the dry ingredients that you had placed in the fridge and the pastry cutter. Add the butter into the dry ingredients. Using the pastry cutter, cut the butter into the dry ingredients until you get small chunks of butter about the size of pea gravel.
Add the wet ingredients to the dry ingredients. Mix with a spatula until just combined. You'll have to get your hands dirty as I have found that some of the flour needs to be worked into the dough. Be careful of over mixing though. You want everything to be just combined and I find this easier to do by hand. Its ok if it feels a bit wet, but it shouldn't stick too much to your hands.
Once you're done mixing the dough, split the dough ball in half and form two six inch discs that are about 1 inch thick. I use a bench cutter to cut the scones and it is exactly six inches across. I use this to measure my discs. I prefer to use my hands to make the discs, but you could roll them out on a lightly floured work surface as well.
Once the discs are on the baking sheet, pop them in the fridge or freezer while the oven preheats to 400 degrees, and do some cleanup.
Once your oven has preheated, remove the baking sheet from the fridge/freezer and cut discs into six triangles. You will want to pull the triangles away from each other, about 1-2 inches, so the sides can cook up nicely. If you want softer sides, you can keep them closer together.
Bake in the oven for 18 minutes. They should look golden brown and a little puffy. You don't want to overcook them. They will continue to cook a bit once you take them out of the oven. Let them cool a bit before enjoying. You want them to be warm but not too hot.
Enjoy with butter, jam, honey, whatever you can think of. Optionally, you can make the vanilla glaze listed below and drizzle on the scones once they have cooled down a bit.