Preheat your oven to 450°F.
In a medium bowl, mix together the flour, baking powder, sugar, and salt.
Pour in the buttermilk and stir until just combined—don’t overmix.
Melt the butter and pour it into an 8x8 baking dish.
Spoon the dough right into the dish on top of the melted butter. Use a spatula to even it out a bit.
Score the dough into 9 squares using a butter knife. It doesn’t need to be perfect.
Bake for 20–25 minutes or until the top is golden and the edges look crisp and buttery.
Let cool slightly, then slice and serve warm.