1. Beat the egg till frothy.
2. Add sugar to it & beat again.
3. Add oil/ghee mix again.
4. Mix blackgramflour, cocoa powder and baking powder thoroughly and fold it in the mixture (of egg,sugar and oil/gee).
5. Put the whole mixture in a glass bowl, lined with butter paper in a microwave oven for 7-8 min on medium power and then grill it for 3-4 mins.
6. The cake is ready.

Note:
Not very high on calorie, this is also suitable for people suffering from celiac disease (wheat allergy).