In a large mixing bowl, whisk together the flour, baking powder, salt, and baking soda.

Add the cold, cubed unsalted butter to the flour mixture and work it into the flour until it resembles coarse crumbs.

Pour in the cold buttermilk and gently blend until just combined.

Transfer the dough to a floured surface and pat or roll it out to about 1½ inches thick.

Using a round biscuit cutter, cut out your biscuits and place them on a baking sheet.

Preheat the oven to 400°F (200°C) and bake the biscuits for 12-15 minutes until golden brown.

Brush the tops of the biscuits with melted butter as soon as they come out of the oven.