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 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.
Scoop the dough onto a lightly floured surface and gently work it together with your hands. Pat the dough into a rectangle and fold it in thirds. Turn the dough, gather any crumbs, and flatten back into a rectangle. Repeat this process two more times.
Using a floured 2.5-inch biscuit cutter, cut out the biscuits. Continue to gather any scrap pieces of dough, patting it back down to 1/2-inch thickness, and cutting it until you have 10-12 biscuits.
Bake for 15-17 minutes, or until lightly golden brown. Remove from the oven and brush with melted butter.