Chocolate Mud Cake

This week, we celebrated Mr Cheeky Monkeys' birthday with our usual dinner and cake chosen by the birthday person.  When I asked the little Cheeky Monkeys what cake I should make for daddy, they both responded, "Something chocolate, of course!"  They know their dad well, because the birthday boy's request was for a real chocolate mud cake, if I could manage that (I'd never made one before).  So off I went and found what looked like a fail safe recipe, hoping that it would produce a decadent mud cake.  And the Cheeky Monkeys' verdict?  The cake tasted great (though it didn't look very pretty), but it wasn't quite "muddy" (i.e. dense and stick to your ribs rich!) enough.  I'm very happy with my attempt, but if you have a really MUDDY mudcake recipe, let me know please!