Preheat the oven to 450°F.
In a medium bowl, whisk together the flour, baking powder, sugar, and salt.
Add the buttermilk and mix just until a moist dough is formed.
Pour the melted butter into an 8x8-inch baking dish and place the dough on top of the melted butter.
Using a spatula, spread the dough evenly across the pan until it touches the sides. As you spread the dough out to the corners, the butter starts to surround it, so it covers every nook and cranny.
Cut the dough into 9 equal squares.
Bake until golden brown, 20-25 minutes. Enjoy!