Preheat your oven to 180 ° C.
Start by making your roll dough: separate the whites from your egg yolks. In a bowl, whip the egg whites firmly. In another bowl, add the sugar to the egg yolks and whisk them. Gently incorporate the two preparation using a spatula.
Mix the flour and the bitter cocoa. Incorporate them in 3 times in the previous preparation. Line a baking sheet with a sheet of parchment paper and spread properly the roll dough. Bake for 8 to 10 minutes.
Once out of the oven, cover it with a damp cloth and turn it over to unmold the sponge roll on the cloth. Use the damp cloth to roll the hot sponge roll on itself and set aside at room temperature, while starting to prepare the Crunchy cream.
Place Nocciolata Crunchy in a bowl placed in a double boiler. Crush the baking chocolate and add it with the whole cream to the Nocciolata Crunchy. Using a spatula and still over the hot spring, mix the ingredients until they are perfectly melted and fold in.
Off the heat, whip the preparation and place it in a pastry bag. Reserve in the fridge for 20 min.
Roll out the sponge roll, pipe over the Crunchy cream and use a spatula to smooth and even out the layer of Crunchy cream.
Zest the orange on top of the cream and roll the dough. Serve in nice portions and enjoy!