Preheat oven to 475°F. Line a baking sheet with parchment paper; set aside. Place flour in a large mixing bowl. Using the larger holes on a box grater, grate the stick of butter into the flour.
Use your fingers to coat all of the butter with flour, and then work the butter into the flour with your finger tips. You should see little bits of flour-coated butter all throughout. Chill in the freezer for 10 minutes.
Make a well in the center of the flour mixture. Add the very cold buttermilk, and stir with a wooden spoon (or with your hands) just until a shaggy dough comes together.
Turn the dough onto a well-floured work surface. Fold the dough over onto itself 6-8 times (this folding creates layers in the biscuits). The dough shouldn't be too wet or sticky. If it's sticking too much to the work surface or your hands, add extra flour as needed. Pat the dough into a rectangle that’s about ¾ inch thick. Use a round biscuit cutter to punch out the biscuits (do not twist the cutter) (I use a 2 ½ -inch cutter, but any similar size works fine). Arrange the biscuits on the parchment-lined baking sheet with sides touching. Re-roll the scraps and cut out additional biscuits until all of the dough is used. If time allows, place the biscuits back in the freezer for 10-15 minutes to chill again before baking.
Bake for 11-15 minutes, or until golden brown. Brush the hot biscuits with the melted butter. Serve warm.