Grease and line on all sides a 900g (9x5in) loaf tin.
Preheat oven to 180C/160C Fan/350F/Gas 4
In a small bowl, whisk together the cocoa powder and the boiling water. Leave to cool.
Blend the mashed bananas and cocoa. Then add the eggs and vanilla and combine. You can use a blender or a whisk.
In a different bowl, add the flour, baking soda, baking powder, sugar, ground mixed spices, and salt. Stir for 30 seconds.
Add the melted butter and half of the wet ingredients. Mix until all dry ingredients are moistened. Add the remaining mixture, mixing for another 30 seconds. You can use a spoon or a hand mixer.
Add the chocolate chips and stir in a circular motion until they are evenly distributed into the batter.
Pour the batter into the tin and bake for 35-34 minutes.
Once baked, leave the cake in the tin for 10 minutes, then carefully remove and leave it on a wire rack until completely cooled down.
In the meantime, prepare the chocolate cream.