Melt the chocolate, sugar and butter together in the microwave on a medium heat or on a bain-marie until all melted together and smooth.
Whisk the eggs, vanilla and sour cream together in a bowl.
Using a whisk or a fork, mix together the flour and cocoa powder making sure it is completely distributed.
Add the egg mixture to the chocolate mixture and mix well.
Fold in the flour and cocoa mixture gently until combined.
Divide equally into the 2 base and side lined 8” round tins and bake for approximately 20-25mins until just firm but still has a little wobble, don’t over bake (if you stick a knife in there should still be a little mixture sticking to it so it is a little fudgy). Then cool in tin for 5 mins before turning onto a cooling rack and removing the paper.
If the ganache is cooled enough, we will now melt the butter and beat in the icing sugar to the ganache, then add the melted butter to complete the frosting.
Wait for the sponges to cool down… then fill and ice the cake - and don’t forget to pop your cherry on top!