Preheat oven to 400°F. Line a baking sheet with parchment paper.
In a large bowl, whisk together the flour, baking powder, sugar, and salt.
Using a box grater, grate the butter over the flour mixture then quickly toss and rub the butter with your hands to incorporate.
Make a well in the middle of the dough then pour the cold buttermilk in the center. Stir until just beginning to come together, then pour out onto a lightly floured work surface.
Bring the dough together into a rectangle, about an inch thick. Fold the dough into thirds.
Using a rolling pin, gently pat back into a 1-inch thick rectangle, and repeat the folding process two more times. Work fast so the butter does not melt.
Once dough is folded three times, roll into a 1-inch thick rectangle again. Using a 2.5-inch round cookie cutter, quickly press down to cut the biscuits.
Place the cut dough on the prepared baking sheet, about half an inch apart.
Brush tops with melted butter, then bake for 20 minutes until golden brown and flaky.
Serve warm, enjoy with family and friends!