Dice the muffin and place in a mug or 1 cup ramekin. Whisk the egg and milk together very well. Pour over the muffin, push down the muffin into the egg and milk mixture. Let sit for a minute then microwave on full power for 2 minutes or until the egg mixture is set.
Three-Minute Three-Ingredient Blueberry French Toast in a Mug https://simplygluten-free.com/blog/2022/01/three-minute-three-ingredient-blueberry-french-toast-in-a-mug.html