In the bowl of a stand mixer, beat the butter, sugar, salt, vanilla and baking soda for 5 minutes, until very light and fluffy.

Add the egg and beat for another two minutes, scraping down as needed.

At once, add the flour, ground hazelnuts, and cocoa powder. Scrape down the bowl and ensure all the dough is mixed well.

Fold in the chocolate chunks.

Place batter in a bowl and cover it with plastic wrap. Set it in the fridge overnight.

The next day, preheat the oven to 350 F.

Portion the dough into 1.5-2 tablespoons of dough onto two parchment lined cookie sheets.

Set the first sheet in the freezer for ten minutes.

Bake for 11-12 minutes, until the edges look set. While the first batch is baking, set the second batch in the freezer. Bake the second batch.