Easy Cinnamon Mug Cake

"If you've ever had the Mondayest Tuesday ever and just desperately wanted to fall deep into the couch with your television remote or favorite book, a steaming cup of coffee, and fresh slice of cake after the kids are down and the house is finally *finally* quiet, then this Easy Cinnamon Mug Cake recipe is for you. Only a handful of totally common (probably in your pantry RIGHT NOW) ingredients and three minutes - prep time included! - will get you there. While the cake is happening, get your coffee on, and take a moment to make sure the hallway door is closed. Sleepy kids who smell cake baking, need not apply."