Preheat the oven to 180˚C. Grease the inside of your pudding steamer with butter.
In a large bowl put the brown sugar, milk and butter and melt it all together in the microwave.
Now whisk in the dry ingredients: flours and cocoa. Mix the eggs together in a jug and whisk them in too.
Whisk until it's all combined. Pour it into your steamer and put it in the oven (no lid) for 40 minutes. Check it after 40 minutes and turn the heat down to 170˚C.
Cook for another 10 minutes or until a skewer comes out clean. Let it cool completely before adding the ganache.
To make the ganache, melt the dark chocolate, butter and cream together in the microwave. Leave it for about 15 minutes to set and thicken.
Cut the bumpy top off your pudding cake, so that you can flip it over and decorate it down side up.
Cover the cake with ganache.
Before the ganache cools completely, start adding the Maltesers. Begin in the centre, forming one row down the middle of the cake. Work outwards from there in lines across the cake.
Put the cake in the fridge to chill for at least two hours.
Once the cake is chilled, melt the white chocolate melts in a bowl in the microwave. Leave them to cool to room temperature before you pour them over the cake (otherwise all the Maltesers will melt.)
Once the chocolate is just at room temperature (don't wait too long or the chocolate will start to set hard again) pour it over the top of your cake so that it looks like the custard on a Christmas pudding.
Finish it off with two Jaffas and some any glossy green leaves you can find in your garden. You could also use the holly from a Christmas decoration.