Heat oven to 425 degrees F. Line a rimmed baking sheet with parchment paper and lightly grease with cooking spray.
In a large bowl, whisk together the dry ingredients.
In a 2-cup liquid measure or small bowl, stir together the chilled buttermilk and melted butter until the butter forms small clumps and the mixture looks curdled.
Stir the buttermilk mixture into the flour mixture with a rubber spatula just until the ingredients are incorporated and the mixture slightly pulls away from the edges of the bowl.
Using a greased 1/4-cup measure or large #20 cookie scoop, portion the dough and drop them onto the prepared baking sheet, spacing about 1 1/2 inches apart.
Bake the biscuits until the tops are golden brown, 13 to 15 minutes. Remove from the oven, brush with additional melted butter. Serve warm.
