In a 14 ounce mug, add in the 2 tablespoons butter. Place into the microwave for 30 seconds.
Add in the 1/4 teaspoon vanilla extract, 1/4 cup whole milk, 2 tablespoons granulated sugar, 1/4 cup plus 1 tablespoon all-purpose flour, 1/4 teaspoon baking powder, and chopped 3 Oreo cookies with filling.
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!
Notes
This mug cake is best consumed within 1 hour of microwaving.