Ingredients
4 tbs flour
4 tbs sugar
2 tbs cocoa
1 egg
3 tbs milk
3 tbs oil
3 tbs chocolate chips (optional)
1/2 tsp vanilla extract
Directions
1. Add the dry ingredients in a large coffee mug and mix well. Add the egg and mix thoroughly. pour in the milk and oil and mix well. Add the chips (if using) and vanilla extract and mix again.
2. Put your mug in the microwave and cook for 3 minutes on high. The cake will rise over the top of the mug, but dont be alarmed! Allow to cool a little, and either tip out onto a plate or enjoy directly out of the mug.

I use cinnamon chips in place of chocolate. Ive also experimented with different extracts and found that while vanilla is the best, orange tastes almost as good.