Direction :

1. In a large bowl, whisk together the flour, salt, sugar, and baking powder. Add the butter and use the back of a fork or a pastry cutter to “cut” the butter into the dry ingredients. The butter should be the size of peas in the end. You can also do this in the food processor: pulse ten times at 1-second intervals.
2. Add the buttermilk and stir with a spatula to combine. You may need to knead the dough briefly with your hands to help the dough form a cohesive ball, but go light — you do not want to overmix here.
3. Turn the dough out onto a lightly floured work surface and pat into a 6-inch square (roughly). Dust a rolling pin with flour, and roll the square into a 14-inch long rectangle. Fold the top third down. Fold the bottom third up. Rotate the dough 90 degrees. Repeat this rolling and folding process twice more. After the final set of folds, pat the dough into a 6-8 inch square. Use a bench scraper or knife to cut the dough into 9 equal portions.
4.  Place a rack in the upper third of the oven, and heat it to 400ºF. Line a sheet pan with parchment paper. Transfer the portioned biscuit dough to the sheet pan and transfer it to the fridge for 30 minutes. Brush the tops of the biscuits with buttermilk and, if you wish, sprinkle with turbinado sugar. Because I find the bottoms of my biscuits to brown too quickly, I set the sheet pan on another sheet pan to bake — do this if you wish. 
5. Transfer the pan to the oven and bake for 25 to 30 minutes. Remove the pan from the oven and transfer the biscuits to a cooling rack immediately.