In a bowl, beat the egg with the sugar, next add the butter, milk and vanilla extract. Then add in the dry ingredients: flour, baking powder, cocoa powder, salt and mix. Stir well to make sure the ingredients are well incorporated

Pour the batter into the mugs. I had it half full, because just like any cake this one is going to rise even if you are cooking this in the microwave

Place one mug at at time in the microwave and cook on medium heat for 2mins. After the 2mins, the cake was done when I made it. You don't want to over do it, cause the cake becomes hard. If the power levels on your microwave are low, you might have to cook it for an extra minute

Allow it to cool before dusting it with some icing sugar. We added some ice-cream to ours ;)

Other things to note:

The microwave should be on microwave mode and not convection mode

Keep an eye on the cake cause you don't want to over cook it!

Choose an appropriate microwable mug :)

You can get really creative and add nuts, or chocolate chips and make it more fun!