In a large mixing bowl, use a whisk to combine the dry ingredients thoroughly.
Cut the cold butter into small cubes and add it to the dry mixture. Using a pastry cutter (or your hands), work the butter into the dry mix until pea-sized pieces remain.Alternatively, I like to place my box grater directly in the bowl and grate the cold butter into the dry mixture. To prevent the butter from sticking to the grater, keep dipping it into the flour mix as you grate. Once grated, use your hands to coat the butter evenly with the dry mixture.
Slowly pour in enough buttermilk until the mixture appears wet and just combined and comes together. Be careful not to overmix.
With floured hands, turn the dough onto a floured surface. Gently press it into a rectangle, then fold it over. using a pastry scraper. Repeat this process 5-6 times. After the final fold, press the dough to a thickness of 3/4 to 1 inch.
Use a round cutter to cut out each biscuit. For the best rise, press straight down with the cutter and lift it back up without twisting it in the dough.Place each biscuit on a parchment-lined baking sheet, spacing them just slightly apart.
Place the baking sheet on the middle rack of the oven and bake until the tops are golden brown, about 12-15 minutes. Once done, remove the biscuits and immediately brush them with melted butter.
Notes
For the lightest and softest biscuits, I prefer using Red Mill Fine Pastry flour.