For one mug cake you need:
1/4 cup powder sugar
2 Tbs of cocoa powder (we didn't have any so we used Nesquik)
Break the egg into a coffee mug. Add the powder sugar and Nesquick. Mix well. The batter should be smooth and glossy looking. Microwave on high for 50-60 seconds.
When the cake is finished the top might still be bubbly but you will have hot and gooey cake underneath. Eat alone or add chocolate chips, whip cream or ice cream.
It might not make a lot of cake but it is so rich you won't need anymore than this.
Be careful, these might become addictive. Cake in 60 seconds? Yes, please!