In a microwave safe coffee mug, melt the butter first. This should only take 10 seconds.
Add the baking powder, almond flour, and egg to the melted butter in the mug.
Stir until all the ingredients have fully combined.
Put the coffee mug back in the microwave for 60 to 90 seconds. (the time will depend on your own microwave power) . My microwave only takes 60 seconds.