Direction :

1. Preheat the oven to 425ºF. Line a rimmed baking sheet with parchment paper. 
2. Whisk together the flour, baking powder, baking soda, sugar, salt, and lemon zest. Grate the stick of butter using a box grater, then scatter the shreds over the dry ingredients.
3. Toss the butter with the dry ingredients and, using your hands, squeeze it gently to disperse it throughout the flour. 
4. Add the buttermilk and the blueberries, and mix gently with a spatula until you don’t see any dry patches in the dough — be patient here. The dough will still be shaggy and will not be a cohesive mass but when pinched, it should hold together. If the mixture seems dry, add a tablespoon more buttermilk (or more as needed). At this point, I now do what I do when I make pie dough: turn the crumbly dough out into the center of a large tea towel, grab the sides and twist the mass into a beggar’s purse, squeezing gently to help it form a disk. Open the tea towel and gently pat the dough as needed to help it come together. 
5. Dust your work surface with flour and turn the dough out onto it. Pat the dough into a 7-inch round circle. Brush the top with melted butter. Sprinkle with sugar. Use a bench scraper to cut the scones into 6 or 8 triangles (I prefer the larger size of the 6 scones, but they are on the large side, so do 8 if you prefer smaller scones.) Transfer the scones to the prepared sheet pan. 
6. Bake until the tops of the scones are lightly browned, 20 to 25 minutes. Remove from the oven, let cool briefly, then serve with butter on the side.