* I can’t always tolerate many of the healthier, gluten-free flours; e.g., sorghum, buckwheat. Therefore, my gluten-free flour mix is 3 parts Asian white rice flour (which is very finely ground) and 2 parts cornstarch. I gently mix three 1-lb bags of the Asian white rice flour and two 1-lb boxes of cornstarch in a very large bowl and then store the mix in several airtight containers. It’s a very economical mix that works well in most recipes. No refrigeration is needed for this flour mix.
If you have certified gluten-free 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).