Preheat oven to 400°F. Spray a 9×5-inch loaf pan with nonstick spray.

In a medium bowl, whisk together flour, baking powder, sugar, and salt.

Pour in the buttermilk and stir until mostly combined, being careful not to overwork the batter.

Pour about 4 tablespoons of the melted butter into the prepared loaf pan, swirling to coat the bottom and sides.

Stir the remaining melted butter into the batter.

Transfer the batter to the loaf pan, spreading evenly.

Bake for 35-45 minutes, or until the top is golden brown and a toothpick inserted into the center comes out with a few crumbs, but no wet batter.

Let the bread sit for a few minutes to allow the butter to be absorbed into the loaf before slicing.

Serve warm.