Mix the caster sugar with the flour in a bowl until you are left with a smooth and consistent butter sugar mix, with minimal lumps. Pre-heat the oven to 180c.

Beat the eggs in a separate bowl, adding to the butter sugar mix with the flour and mix all the ingredients together.

In another bowl, mush two bananas until smooth, add the peanut butter (and Nutella if you're substituting for the dark chocolate chunks). Mix until smooth and add to the butter-flour-eggs mix.

Add the baking powder to the mix and stir until smooth.

Prep your cake tin with butter, spreading around the tin to act as a glue. Next, add greaseproof paper and apply more butter inside to stop the mix from sticking after the bake.

Add the batter, making sure you get all of it into the tin. In a grid-like manner, add squares of your dark chocolate and submerge just below the surface so that they're only just visible. This will mean that they're gooey and in the middle of the cake once baked.

Slice the last banana and add to the top of the mix in the tin on top of the chocolate grid. Sprinkle brown sugar on top and place in the middle of the oven.

Leave to bake for 30-35 minutes. Do not open the oven during baking as it may sink. Keep an eye on it to ensure it's not burning. Leave to rest for an hour after baking, then remove from the tin to air for another 30. Slice and enjoy!