In a 14 oz. mug, add in the butter. Place into the microwave for 30 seconds.
Add in the vanilla extract, sugar, flour, cocoa powder, baking powder, milk, and peppermint chips.
Stir until the mixture comes together and most of the lumps are gone.
Place into the microwave for 1 minute 30 seconds to 1 minute 45 seconds. I've had the best luck with 1 minute 45 seconds.
Let cool for a minute or two.
Grab a spoon and enjoy!
Reserve a spoonful of peppermint chunks and sprinkle on the top of the batter just before microwaving. This will ensure that there will be peppermint chunks at the top of your cake.The cake is best consumed within the first hour of microwaving.