2 tablespoon of Self-raising flour
2 tablespoon of castor sugar
1 tablespoon of dark cocoa
1 tablespoon of instant coffee
1 table spoon of milk
1 table spoon of sunflower oil
If you want to, you can add chocolate chips.
You can replace self-rising flour: regular flour with some baking powder. 3 tsp. of baking powder for every 8 oz. of regular flour. Recommended in this case, considering that 2 tbsp. = 1 oz., you're going to need 2 tbsp. of regular flour and 3/8 tsp. of baking powder.
For castor sugar, you can use regular granulated sugar and run it through the food processor or try confectionery sugar.
For sunflower oil could substitute canola oil (not sure about olive oil) more of the "flavorless" oils.
Prepare the cake in a mug :
1. Get a mug, wide but not too tall.
2. Put the self-rising flour (or regular flour and baking powder), sugar, cocoa and coffee powder into the mug and mix it thoroughly. Fork better than a spoon.
3. Add the eggs in and mix it all together with a fork.
4. Add in oil and milk and mix it all very well.
5. Add in some chocolate chips. (I replaced this with a regular, plain chocolate bar and it worked pretty much the same way.)
6. Place in the microwave on full power for 2½ minutes.
7. Leave to cool for one minute or you'll burn the roof of your mouth.
Adapted from Article Source: http://EzineArticles.com/6165944