In a large bowl, whisk together flour, baking powder, baking soda, and salt.
Using a pastry cutter, incorporate the butter into the drying ingredients leaving large chunks. Do not use hands as it will melt the butter. You may also blitz in the food processor for a few seconds.
Fold in buttermilk until a thick, shaggy dough forms.
Lightly flour a clean surface and dump the dough into it. Bring the dough together until it comes together in one large piece.
Roll out with a rolling pin to about 1 ½ to 2 inches. Using a biscuit cutter or small glass, cut out 2-3 inch rounds and place them on the prepared baking sheet.
Bake for 18-20 minutes until golden brown. Brush the biscuits with melted butter.