1. In a mixing bowl, add flour, sugar, and cocoa powder.
2. Drop egg, oil, and vanilla extract in it.
3. Add baking powder and mix well.
4. Pour coffee and whisk well to avoid egg from scrambling.
5. Into greased micro oven proof dish, transfer the batter.
6. Pop it in oven on for 8 minutes on high.
7. For ganache, take a microwave safe dish, and drop chocolate, milk, butter, and vanilla in it.
8. Place bowl in oven for about a minute. Remove from oven and mix well.
9. Pour chocolate ganache on top of cake to cover it completely.
10. Cut chocolate cake into slices and serve immediately.