Chocolate sponge cake :
½ cup sugar
½ cup of flour
2 tablespoons of cocoa powder
¼ cup crushed and toasted hazelnuts
Nutella and dulce de leche buttercream:
165 g butter
125 ml of nutella
185 g milk jam (dulce de leche)
100 g water
50 g sugar
½ tsp vanilla extract
For the filling:
crushed and roasted hazelnuts
100 g milk chocolate
Prepare the chocolate sponge cake:
Preheat the oven to 180 C (350 F).
In a bowl, beat sugar and eggs at high speed for about 12 minutes or until mixture doubles in volume.
Mix together cocoa and flour. Sift the mixture.
Gently fold in the flour and cocoa mixture in three batches.
Add the roasted and crushed hazelnuts.
Gently pour the sponge cake onto a baking sheet covered with parchment paper.
Place in the oven for about 12 minutes and test with your finger by pressing on the surface of the sponge cake, which should rise immediately.
Turn the sponge cake onto a clean cloth and roll it up immediately. Leave to cool.
Prepare the Nutella buttercream:
Place the soft butter (room temperature) as well as the milk jam (dulce de leche) and the nutella spread.
Beat at medium speed until the mixture becomes clear and smooth. Scrape down the sides from time to time.
Bring water and sugar to a boil for 3 minutes. Remove from heat and add vanilla extract.
Unroll the cake and soak the surface with syrup.
Spread the buttercream over the entire surface.
Sprinkle with crushed hazelnuts and place a few ferrero rochers if desired on the bottom edge of the roll.
Gently roll up the sponge cake. Film and chill for 1 hour.
Cover the roll completely with nutella buttercream. Sprinkle with crushed hazelnuts.
Decorate with Ferrero Rocher chocolate.
Melt chocolate in a double boiler. Let cool and then pour into a small ziploc bag, cut the edge and decorate the roll in a zigzag shape.
Place in a cool place until ready to serve.