In a small bowl, mash the banana. Whisk in the almond milk, maple syrup, and almond butter.
Add the cocoa powder, almond flour, oat flour, baking powder, espresso powder, and sea salt and whisk until no lumps remain.
Divide the cake batter between two mugs. Sprinkle the top with extra sea salt. Microwave one at a time for 60 seconds each, then let sit in the microwave another minute before opening the door. (This may vary based on the power of your microwave.) Enjoy immediately!
Recipe by Coffee & Quinoa at https://www.coffeeandquinoa.com/2014/11/salted-chocolate-almond-mug-cakes-vegan-and-gf/