Preheat oven to 350℉ (175℃) and grease a 9"x5" loaf pan.
In a large bowl, whisk flour, sugar, baking powder, and salt.
Make a deep well in the middle of the mixture and slowly pour in the beer. Stir until combined. The dough should be a little sticky. Then add vanilla extract and combine again.
Pour half of the melted butter into the bottom of the loaf pan and spread it out evenly, making sure the surface is coated.
Then add the batter to the loaf pan and spread it out evenly. Pour the remaining half of the melted butter over the top of the batter.
Bake it in the preheated 350℉ (175℃) oven for 40-50 minutes or until the bread is golden brown on the outside and a toothpick comes out clean when inserted in the middle.
Let rest for 5-10 minutes, slice, and serve.