The first step is to turn the hazelnuts into hazelnut butter. Start by adding the hazelnuts to a food processor.

Blend the hazelnuts on high speed for a full minute. Then pause to scrape off the sides. Blend again for another minute and pause again to scrape off the sides. Repeat this process at least 5 or 6 times, until you have a creamy liquid consistency. This is your hazelnut butter.

Transfer the hazelnut butter into a large bowl. To it, add the sugar, cacao, melted chocolate, flour, baking soda, vanilla, salt and milk.

Combine the ingredients well and form the dough into balls, about 1 inch in diameter.

Line the cookies on a baking tray. Gently pat the tops of each cookie to flatten them a bit.

Bake in the oven for 10 minutes at 350*F/ 175*C.

Allow the cookies to cool for at least 30 minutes. Melt some chocolate and dip half of each cookie in the chocolate. Sprinkle with crushed hazelnuts.