Preheat the oven to 375°F. Lightly grease a 9" x 5" loaf pan., Mix the flour, sugar, 3 tablespoons of the melted butter, and the beer, stirring until fairly smooth; don't worry about a scattering of small lumps., Spoon the batter into the prepared pan, smoothing the top. Drizzle with the remaining 1 tablespoon melted butter., Bake the bread for 45 to 50 minutes, until a toothpick inserted about 1/2" into the top of the loaf comes out clean, or with a few moist crumbs clinging to it., Remove the bread from the oven, and after 5 minutes turn it out onto a rack to cool., Wait until the bread cools completely before slicing. Store airtight at room temperature.