Preheat the oven to 375°F. Weigh your flour, or measure it by gently spooning it into a cup, then sweeping off any excess. , Whisk the dry ingredients together in a bowl. Use your fingers to work the cold butter into the dry ingredients. , Stir the eggs, yogurt, vanilla extract, and lemon zest or oil together. Add to the dry ingredients and stir just until combined. Stir in the blueberries. This dough is the consistency of a wet drop-cookie dough., Liberally flour your counter and your hands. Take the dough out of the bowl and place it on the counter. Pat it into a 1" thick rectangle. Cut into 10 triangular scones. Place on a well-greased or parchment-lined baking sheet., Brush the scones with melted butter, and sprinkle with sugar. Bake for 20 minutes, or until lightly browned and a toothpick or cake tester inserted into a scone comes out dry. Cool completely on a rack., Scones are best enjoyed fresh from the oven, or within several hours of baking. If you do have leftovers store them, well wrapped, at room temperature for a day or so; freeze for longer storage.