Preheat your oven to 180°C/350°F/Gas 4. Line a 25x20cm (10x8") baking tray with baking paper.Place the chocolate (for the batter) and butter into a microwave safe bowl. Heat in the microwave until fully melted. Alternatively, place the bowl over a saucepan of boiling water and melt.
150 g Chocolate, 200 g Butter
In a separate bowl, add the brown sugar and eggs (a). Whisk together for 3-4 minutes, until light and fluffy (b).
3 Egg, 275 g Light brown sugar
Pout the chocolate mixture into the egg mixture with the vanilla. Fold together very gently.
1 teaspoon Vanilla extract
Add the flour and cocoa powder to the mixture.
100 g plain flour, 50 g Cocoa powder
Carefully fold in the flour and cocoa. Add 2 packs of the Kinder Bueno pieces and the remaining chocolate chunks. Carefully mix again.
2 pack Kinder Bueno bars, 50 g Chocolate
Pour the batter into the lined baking tray and top with more Bueno pieces.
1 pack Kinder Bueno bars
Bake for 25-30 minutes. Remove from the oven and allow to cool. The brownies will seem uncooked when removed from the oven, but they will continue to cook in the tray.
If you want to continue with the hazelnut theme, then you can put a drizzle of melted Nutella on top of the brownies before serving.
When beating the eggs and sugar, make sure to beat it until it doubles in size.
When adding the flour and cocoa, fold it in very gently. Do not over-mix, otherwise the brownies will be too dense.
Let the brownies cool before serving. I would recommend putting them in the fridge for a couple of hours (or even overnight) before cutting.
Make sure your eggs are room temperature before baking.
Make sure to line your tin with grease proof paper so the brownies come out easily.