Start with the bread. Dice, cut, and/or cube bread so that it's able to fit comfortable in the coffee mug.
Melt butter in cup for a few seconds in your microwave. Swoosh it around the cup to cover the entire inside.
if substituting olive oil, skip warming the oil, and just swoosh it around your cup.
Add your diced bread pieces to your cup
In a seperate cup, or bowl, mix the egg, the milk, dash of cinnamon, and the drop of vanilla extract. Stir!
Pour liquid over the bread. Smush the bread slightly to allow the mixture to soak all throughout the cup.
Microwave time! Place microwave-safe mug into the microwave and start with 1 minute, then set 10 secs at a time until it is cooked to yoyr liking (or until there i no more egg running).
Add syrup as desired, and enjoy your microwaved delicacy!