Preheat oven to 450 degrees F. Line a baking sheet with parchment paper or a silicone baking mat.
In a large bowl, combine flour, baking powder, salt and baking soda. Cut frozen butter into small cubes, or use a box grater to shred (this makes it SO easy!) Work butter into the dry ingredients until it resembles coarse crumbs. Stir in buttermilk using a rubber spatula, until a soft dough forms.
Working on a lightly floured surface, knead the dough 3-4 times until it comes together.Using a rolling pin, roll the dough into a 1 1/4-inch thick rectangle. Cut out 10-12 rounds using a 2 1/2-inch biscuit or cookie cutter. Place biscuits onto the prepared baking sheet; place in the freezer for 15 minutes.
Remove biscuits from freezer and brush tops with butter. Place into oven and bake for 15-18 minutes, or until golden brown. Serve warm.