Prep. time: 45 minutes
Cooking time: A few minutes
Chilling time: 4 to 5 hours

 Caramel

1. Place the sugar in a saucepan and cook over low heat without stirring until it forms a blond caramel. Meanwhile, heat the 150 g liquid cream with the vanilla.
2. Soften the gelatin in a bowl of cold water.
3. When the caramel is cooked, remove it from the heat and add the butter, piece by piece, the beaten egg yolks and hot cream and stir well. Stir in the drained gelatin sheets and allow the mixture to cool. 

Ganache

1. Melt the chopped dark chocolate in a double boiler.
2. Add the cream and stir well with a wooden spoon until smooth. Refrigerate the ganache until thickened but still workable.
3. Place the ganache into a piping bag fitted with a plain tip.

Assembly

1. Line a Yule log tin or loaf pan with plastic wrap.
2. With an electric mixer, beat the remaining cream to stiff peaks, then fold it into the cooled caramel cream.
3. Fill the pan with half the caramel mixture.
4. Place in the freezer for 10 minutes, then pipe a line of ganache down the center lengthwise.
5.  Cover with the remaining caramel mixture and refrigerate for 4-5 hours.

Icing

1. Place the gelatin into a bowl of cold water.
2. In a saucepan, combine the water with the cream and sugar and bring to a boil. Add the cocoa and simmer for 2 minutes.
3. Remove from the heat and add the gelatin which you have squeezed dry; mix well and let cool. 

Finishing

1. Crush the hazelnuts and toast them briefly in a dry skillet. Sprinkle with brown sugar, allow to caramelize and transfer to a piece of parchment paper.
2. Unmold the Yule log onto a rack. Pour the cooled glaze over top, wait a few moments, then decorate the log with the caramelized hazelnuts and some sugar sprinkles.