Drizzle some additional maple syrup over your mug pancake before eating. Enjoy!
If you have certified gluten-free purity protocol oats, you can process them into oat flour using your food processor or spice grinder.
Your Mug Pancake will rise very high while baking, with some of the batter possibly running over the side of the mug, but then the batter will settle back down.
For those who don't use a microwave oven, gfe reader Kelly shared that she's "been doing some muffin in a mug recipes in my toaster oven at 350F for 15 min in one of those glass custard cups." I'm sure individual mug pancakes would work in a conventional oven, too, either using glass custard cups or ramekins (although when baked in the latter, the cooking time would most likely increase a bit due to the thickness of the ramekins).
Recipe by gfe--gluten free easily at http://glutenfreeeasily.com/gluten-free-mug-pancake/