Grease and dust the cake tin with flour to prevent the cake from sticking.
Separate the egg white into a dry and clean vessel and the yolk in another vessel.
Beat the egg white till white soft peaks appear and no more liquid is left. Takes approximately 5-8 minutes.
Double boil the chocolate pieces. Stir occasionally, the chocolate will melt in approximately 5 minutes. (How to: Heat ¼ cup water in bigger vessel and place smaller vessel with chocolate into the bigger vessel.) Preheat the oven at 250°C for .
Whip/Pulse wheat flour, baking soda and baking powder for 10 sec in a mixie or use food processor. Do this 5 times. OR You can also alternately sieve the dry ingredients thrice. Add the butter and sugar to a big mixing bowl. Whip it well till its soft.
Add egg yolk to this and beat it well.
Add the lukewarm chocolate liquid to this and beat it. (Do not overbeat!)
Add the orange juice and mix.
Add the flour mix to this in three to four batches and mix well.
Finally, fold in the egg whites.
Pour the batter into the cake tin and then tap the tin twice on the kitchen slab to release any trapped air.
Bake at 180°C for 30 to 35 min or until the toothpick comes clean.
Decorate and enjoy the freshly baked cake or just have it as is!