4 tablespoons flour
4 tablespoons sugar
2 tablespoons cocoa
3 tablespoons milk
3 tablespoons oil
3 tablespoons chocolate chips (optional)
a small splash of vanilla extract
1 large coffee mug
Add dry ingredients to mug, and mix well. Add the egg and mix thoroughly. Pour in the milk and oil and mix well. Add the chocolate chips (if using) and vanilla extract, and mix again.
Put your mug in the microwave and cook for 3 minutes at 1000 watts (high). The cake will rise over the top of the mug, but don't be alarmed! Allow to cool a little, and tip out onto a plate if desired.
My version wasn't quite the same. I didn't use any sugar but a tbs of honey and I didn't use oil but a lump of butter melted in the cup before I added the dry ingredients. I also used self-raising flour because that's all we had. The batter turned out to be very runny but that didn't matter because it expanded to reach twice the height of the cup before collapsing back on itself. If anything I think 3 minutes was slightly too long, 2 1/2 would have done. I don't think it matter in which order you mix things either.
The end result was not quite sweet enough so after cutting the cake into pieces I sprinkled on about a level teapsoon of sugar. It was still pretty hot so the sugar melted.
And to my surprise, especially given the negative reviews elsewhere on the web, it was pretty good. The texture was slightly too dense but the flavour was chocolately and it was nicely moist.
I've now got 5 eggs left so it's cake everyday of the week!