In a large bowl, whisk to combine flour, baking powder, salt and sugar. Add beer and use a wooden spoon to combine.
Coat the inside of a 9x5" loaf pan with half the melted butter (2 Tablespoons). Add batter to pan, then pour over the remaining melted butter.
Bake for 45 minutes or until the top is set and a toothpick inserted into the center comes out clean. Let cool in pan for 10 minutes, then carefully remove from pan and transfer to wire rack to cool completely.
Choose a beer whose flavor you enjoy! Just avoid non-alcoholic beers, as you need yeast in the beer for the recipe to work.
Let it cool completely before you slice so it doesn't fall apart.