Bake the hazelnuts and grind them. Fill the nuts with water and soak them, then strain through a gauze.
Mix them with flour and sugar and put the mixture to boil over low heat, stirring constantly, until thickened. Beat the yolks with 2/5 cup (100 g) sugar and separately mix the cold milk with the flour and remaining sugar.
Add the yolk mixture to the flour and stir well. Place to boil over low heat and stir until thickened.
The hazelnut dough get put in a bowl and left to cool in the refrigerator. Soon as it is cooled down, pour the already prepared milk cream. Sprinkle with chopped nuts and serve