Preheat the oven to 375°F. Sift the dry ingredients together in a bowl. Add the butter and rub it into the dry ingredients with your fingers.
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-inch-thick rectangle. Cut into 10 triangular scones. Place on a well-greased cookie sheet.
Brush with melted butter and sprinkle with sugar. Bake for 20 minutes, or until lightly browned and a cake tester inserted into a scone comes out dry. Cool completely on a wire rack.