Preheat oven to 425º F (218º C). Line a cookie sheet with nonstick parchment paper. Set aside.
Combine flour, baking powder, sugar, and salt in a large bowl and mix well. Set aside.
Use a pastry cutter to cut cold butter into the flour mixture, until the mixture resembles coarse crumbs. Note: you want to see small, pea-sized pieces of butter throughout the dough. If you don't have a pastry cutter use your finger.
Add in the buttermilk and mix with a fork until the ingredients are combined. The dough will be sticky. You should be able to see the butter pieces in the dough.
Transfer your biscuit dough to a well-floured surface and use your hands to gently work the dough together. If the dough is too sticky, add flour, 1 tablespoon at the time, until it is manageable.
Once the dough is consistent, fold in half over itself and use your hands to gently flatten layers together. Rotate the dough 90 degrees and fold in half again, repeating this step 6 times but taking care to not overwork the dough.
Gently pat out the dough some more, so that the rectangle is roughly 10 inches by 6 inches. The dough should be about 3/4 inch thick. Cut dough into biscuits using a floured glass or biscuit cutter. Do not twist cutter when cutting; this crimps the edges of the biscuit and impedes its rise.
Place biscuits on a cookie sheet. If time allows, refrigerate the biscuits for 15-20 minutes, this short chill will help them maintain their shape while baking. This is totally optional, if you are in a rush, go ahead to the next step.
Brush the top of the biscuits with heavy cream, to enhance browning (optional). Bake until golden brown, approximately 10 to 15 minutes.