What to do if you can't find hazelnut meal: toast whole hazelnuts in a pan for few minutes.Pay attention not to burn them.Let them cool then put them in a mixer with the icing sugar written in the recipe.Mix them doing pauses to avoid hazelnuts release their oil, pulse and pause, pulse and pause.Stop when you have a fine meal, put it in the fridge for 15 minutes before using it. Mix hazelnut meal with icing sugar if you didn't do before, then add salt and diced cold butter.Make a dough using the mixer, add egg and mix again.
You will end with a sticky dough, wrap in cling film and let it rest in fridge until hard.
Take pieces of the dough and roll it between your hands, you must end with a ball of about 1.5 cm/ 0.5 diameter.Do it with all the dough, put the balls without pressing them on a lined baking tray.
Put the baking tray into the freezer, let them rest at least one hour before baking.
Bake in preheated oven at 350°F/ 150°C for 5 minutes, then low temperature to 230°F/ 110°F for 10-12 minutes more.
Take the tray out of the oven and let them cook completely before touching them, they are very soft at this point.
Melt chocolate using the bain marie technique, it must be a melted but not too liquid, if it is let it cool a little.
Put some chocolate on the flat part of a cookie and pair it with another to form the kiss.
These cookies can be stored up to a month in a tin box.