For the filling, mix the hazelnuts, sugar, vanilla sugar, cinnamon and the egg. Depending on the consistency, add a little milk if necessary.
Roll out the cooled puff pastry and distribute the filling evenly on top. Roll up the puff pastry, cut into pieces about 1 cm wide and spread on a baking sheet lined with baking paper. Leave some space between the individual snails. Bake in a preheated oven at 200 ° C (convection 180 ° C) for about 15-25 minutes until the desired brown color is achieved.
Let the snails cool down well after baking.
For the glaze, mix 1 - 2 tablespoons of powdered sugar with a little water and brush the snails with it. Then let the glaze dry well.