In a large bowl combine ground hazelnuts, baking chocolate, powdered sugar, egg white, and rum. Using a wooden spatula combine the ingredients as much as you can.
Note: you can use grated chocolate (our preference, look at the photos), or melted chocolate (look at the video).
Grease your hands generously. Using your hands, mix the batter vigorously. At first, it may feel as if the ingredients will not stick together. Keep mixing them with some strength and in about a minute or two, the batter will take on a consistency of wet sand.
Taking some batter in between your fingers, form little balls. Start by sticking the batter together, and then roll it between your palms until a small ball forms (sized between a large marble and ping pong ball). You should have between 28-30 balls, approximately.
Pour chopped hazelnuts onto a plate and roll each ball in it. Set balls aside on parchment paper for a few hours, so they dry up. Transfer them to a cookie box.
Storing: Keep hazelnut chocolate balls in a dark, cool place, (or the fridge). They will keep for 5-7 days.Serving: serve 2-3 balls per person along with coffee, or a refreshing drink.