Chocolate-hazelnut roll cake
For the sponge cake
90 g of powdered sugar
100 g of flour
1/2 sachet of baking powder
1 sachet of vanilla sugar
For the chocolate ganache
200 g milk chocolate
65 g full cream
For the rocher glaze
250 g milk chocolate
40 g neutral-tasting vegetable oil
70 g hazelnut chips
The sponge cake
Preheat the oven to 180°C.
Whisk the egg yolks and sugars in a bowl for a few minutes until the mixture turns white. Add the flour and baking powder and mix.
Beat the egg whites until stiff and fold in gently.
Pour onto the sponge cake tin and bake for 10-12 minutes at 180°C.
Take the mold out of the oven, and turn the sponge cake on a damp cloth. Roll up the sponge cake and let it cool.
Melt the chocolate in a bain-marie. Once melted, emulsify it with the hot cream (pour the cream in 3 times while mixing briskly).
Unroll the cookie, then, using half a spatula, fill it with the ganache. Roll the cookie again.
Set aside in the refrigerator for 1 hour.
Melt the chocolate in a double boiler. Add the oil and hazelnut chips. Pour the glaze over the cold rolled cake and let it run down the sides. Let the icing set for 30 minutes at room temperature or in the fridge before serving.