Whisk the butter with sugar until fluffy. Add the oil gradually while whisking the mix.Mix the cocoa with hot water till it dissolves. Then whisk in the yoghurt and vanilla extract into it.
Sift the flour, baking soda and salt together. Keep aside. Now into the butter mix, add in the eggs while whisking it.
Now fold in the sifted flour mix and the cocoa mix into the butter - egg mix in 3 parts alternatively.
Divide or pour the batter into 2 greased cake tins (20 can diameter each), and bake these at 180 ℃ for 30-35 minutes or until the toothpick inserted comes out clean. Let the cakes get cooled completely.
To prepare the frosting, melt the chocolate using double boiler method (melting the chocolate in a heatproof bowl placed over a saucepan of simmering water).
Now whisk the butter until smooth and then add the icing sugar . Whisk further and add the vanilla extract.
Then add the melted chocolate into the above and whisk until desired consistency is attained.
Now apply some of the frosting generously on one of the cakes. Place the other cake on top.
Cover layered cakes with the frosting and decorate as desired. I have also used lots of chocolate shavings on top.
