Preheat your oven to 180°C/356°F top to bottom heat.
To ensure that the bowl is uncontaminated, wipe it with some lemon juice or vinegar. This will ensure that your eggs will be nice and stiff. Now place the egg white in the bow.
6 egg whites, lemon juice or vinegar
Add a pinch of salt and then using a hand or stand mixer, whisk the egg whites until stiff. Set aside in the fridge until needed.
1 pinch salt
In a separate bowl whisk the butter, sugar and milk until creamy.
225 g butter, 300 g sugar, 1 tablespoon milk
Prepare a water bath and melt the semi-dark chocolate. (To make a water bath: place a bowl over a pot of simmering water. Chop up the chocolate into small pieces and place it in the bowl. Stir occasionally to avoid bubbles forming. When the chocolate almost melts, carefully remove the bowl from heat and place it on a towel. Stir until all the chocolate is melted and ready to use. )
150 g baking semi dark chocolate
Add the flour, baking powder and hazelnuts to the butter mix. Pour in the melted chocolate. Mix to a smooth cake batter.
180 g flour, 2 teaspoon baking powder, 200 g ground hazelnuts
Finally, add in the stiff egg whites. Carefully mix until combined. You do not want to mix too long otherwise the egg whites will deflate and the cake might not end up as airy.
Prepare a cake form or a bundt cake form by greasing it with butter and dusting the metal with flour.
Pour or spread the cake batter in the form and place in the oven.
Bake for approximately 50 minutes. Test the cake by piercing it with a skewer. If the skewer comes out clean the cake is ready.
Leave to cool completely.
Decorate by pouring over some semi dark cake icing, or simply dust with some powdered sugar.