Heat the oven to 350°F (175°C) and grease a 9-by-5-inch loaf pan. For an especially crisp bottom crust, brush a little of the melted butter inside the pan.

Whisk the self-rising flour and granulated sugar together in a large bowl. If using all-purpose flour, whisk in the baking powder and salt as well.

Pour in the beer and stir just until the dry ingredients are moistened. Keep the batter thick and somewhat lumpy, because overmixing can make the finished bread dense or tough.

Scrape the batter into the prepared loaf pan and smooth the top lightly. Pour the remaining melted butter over the surface so it can soak into the top as the loaf bakes.

Bake for 45 to 55 minutes, or until the loaf is deeply golden and a skewer inserted in the center comes out clean. Begin checking near the 45-minute mark because oven temperatures and pan materials can vary.

Cool the bread in the pan for about 10 minutes, then transfer it to a wire rack. Let it cool for another few minutes before slicing so the crumb can finish setting.