Preheat oven to 180'C.
Butter a 23cm/ 9" round cake tin and line the base with greaseproof paper.
In a food processor blitz the rice until ground into a powder.
Melt the chocolate in a bowl over a pan of simmering water. In another bowl, whisk the butter and the caster sugar together until pale and fluffy then gradually beat in the eggs one at a time. Lightly fold in the flour, ground rice and vanilla. Finally, fold in the melted chocolate and the espresso.
Pour the mixture into the prepared cake tin and bake for approximately 15 minutes or until a skewer inserted into the centre of the cake comes out clean.
Allow to cool in the tin for 30 minutes before turning out.
Break the chocolate into pieces and place into a heatproof bowl.
Place the cream and butter into a heavy based pan and bring to the boil. Pour the hot liquid over the chocolate and whisk until smooth. Allow the ganache to cool and set for a few minutes before pouring over the cake. If you want to be more creative you can use a fork to make patterns in the chocolate. Chill the iced cake in the fridge for 10 minutes to set a little.
«For a lighter cake which is not as rich, use milk chocolate instead of dark chocolate.»