Preheat the oven to 375 F (190 C).
Grease a 9×5 inch (23 cm x 12.5 cm) bread loaf pan.
In a bowl, combine the flour, baking powder, salt, and sugar.
Pour in the beer and mix until everything is well combined.
Pour the batter into the prepared pan.
Pour the melted butter over the top of the batter.
Bake for 40 to 45 minutes or until a toothpick inserted into the center comes out clean and the top is golden brown.
Let cool in the pan for 5-10 minutes before serving.