Preheat the oven to 165℃. Line a 22x32cm baking tin with baking paper.

Cut the butter into chunks, place in a heat proof bowl along with the dark chocolate and melt it over a pan of simmering water until there are no lumps left, take off the heat and set aside to cool slightly.

Use an electric whisk to beat the eggs, egg yolk and the sugar until it is pale and thick, it should double in size.

Pour the melted chocolate into the egg/sugar mix and fold through, be careful not to knock the air out of it. Use the figure of 8 method, going around and under.

Use a sieve to add the flour and cocoa. Fold the mix all together, then fold through the Kinder Bueno and Kinder chocolate.

Pour the fudgy mixture into a lined baking tray and spread the mix into the edges.

Place in the oven at 165℃ for 22-25 minutes. It should have a slight wobble in the middle and will have formed a paper like crust.

Leave it to cool until it is at room temperature. I like to put it in the fridge for a few hours before cutting it into portions. Enjoy.