To prepare this simple recipe, combine the dry ingredients in your coffee mug and set them aside. Next, in a small bowl, microwave butter with milk for a few seconds until butter is fully melted. Make sure the mixture doesn't boil or overheat.
Combine the liquid ingredients with the dry ones in the coffee cup, mixing until just combined. Be careful not to overmix and make sure there are no dry spots left at the bottom of the mug. Let the batter rest for 2 minutes.