Preheat the oven to 400° F and line a large baking sheet with parchment paper or a silicone baking mat.
Use a food processor to pulse together the flour, baking powder, baking soda, and salt. Add in the well-chilled butter and pulse just until the mixture is crumbly. Add the buttermilk and pulse until just mixed.
Prepare an area on the counter to roll out the biscuits by sprinkling flour on the surface of the counter. Place the dough onto the counter. Cover a rolling pin with flour and gently roll out the dough into a rectangle shape.
Fold one third of the dough onto itself, and then fold the opposite ⅓ of the dough onto it. Think of it like folding a letter.
Now press the dough into a rectangle about ½ inch thick. Use a 2 ½ inch round cookie cutter to cut out as many biscuits as you can. Place these on the baking sheet. Gather up the scraps of dough and again press it out to ½ inch thick. Continue doing this until all the dough is used up.
Brush the tops of the biscuits with a little buttermilk.
Place the biscuits in the oven to bake for about 12-15 minutes or until golden.