Add all ingredients to the bowl of your food processor and process until well incorportated and hazelnuts are reduced to small chunks.
You will have to scrape the sides and push the mixture to the bottom quite a few times. You might find that pulsing helps the mixture stay longer at the bottom of the bowl.
When all is good and well incorporated, transfer the mixture to a small square pan and press down firmly and evenly to form a rectangle of approximately 8 x 6 (I used a 8 x 8 pan but only used 2/3 of its surface)
Use a spatula to make the top and sides as flat and smooth as possible.
Cut into 12 bars and refrigerate. These bars will keep for a few weeks providing that your Nutella has just been made, or that your egg whites are as fresh as can be!
*Tip: Wrap individually in parchment paper for extra portability.