Whisk egg, breadstick crumbs, powdered hazelnut, flour, cinnamon, oil, and vanilla in a mixer for 5 minutes; pour the dough into lubricated tray and cook at 220 0C temperature for 6 hours; let cool for a while; to prepare its cream, boil liquid cream and add milky chocolate, instant coffee and butter and whisk in blender for 5 minutes. Let it rest at 0 0C temperature for 24 hours. Divide the cake into five pieces. Put one piece of cake in a oval-shape container; whisk the prepared cream in a mixer for 7 minutes; smear a bit on the cake. Put other piece of the cake and pour rest of the cream; arrange syrup-candied chestnuts over it and cover with last piece of the cake. Let rest at 0 0C temperature for 4 hours; incise milky-chocolate with tip of the tablespoon and attach on sides of the prepared cake; put chestnut paste in cream bag and strain over the cake as you wish.
