First microwave 350g of nutella and add to your mixing bowl.
Next crack 2 eggs into a mug or separate bowl so no shell gets into your mix and then add the eggs into your mix with a third egg yolk.
After you have put the eggs and yolk into your mix, get your electric whisk and whisk until the batter is smooth.
Next fold in 62g of flour into your mix and make sure there is no flour on the edges of your bowl.
Now pour your mix into a cake tin lined with baking paper and put in the oven to bake for 20-25 minutes or until baked evenly through.
Finally take out of the oven and let cool for around 30 minutes to an hour, then cut into squares and serve.