In a small bowl, whisk together the dry ingredients until combined. Add the wet ingredients and mix until smooth.
Transfer to a greased microwave-safe mug and microwave for one minute.
Remove the mug cake from the microwave and let it sit for 30 seconds before enjoying.
Notes
STORAGE: Mug cakes are best enjoyed fresh so I don't recommend storing it to enjoy later. If you do have any leftovers, cover in plastic wrap and keep it for up to one day.