Place the caster sugar, cocoa powder, plain flour and baking powder in a large bowl and stir to combine. Set aside.

In a small bowl whisk together the vegetable oil, vanilla extract and eggs. Pour into the dry ingredients followed by the boiling water. Whisk to combine. Fold through the chopped chocolate with a spatula or wooden spoon.

Remove the inner pan and lightly spray with cooking spray. Pour in the cake batter then return to the rice cooker.

Select the 'Cake/Bread' setting and dial in 40 minutes.

Whilst the cake is baking, make the chocolate ganache. Heat the cream in a small saucepan over low heat. Just before it starts to simmer remove from the heat and add the chocolate. Allow to sit for 5 minutes before stirring with a spatula or wooden spoon. Place in the fridge for 1 hour until thick enough to spread.

When the cake is ready, remove the inner pan from the rice cooker. Place a plate over the top of the inner pan and flip the cake out. Place a wire rack on top of the cake and flip again. Allow to cool completely.