With a whip, blanch the previously melted butter and the icing sugar.

Progressively incorporate the egg yolk and the cocoa powder.

Incorporate the sugar in the egg whites and raise them.

Mix the melted black chocolate with the previous preparation.

Delicately incorporate the meringue.

Spread the biscuit on baking paper over a surface of 29 x 20cm.

Bake at 200 °C during 6 to 8 minutes (being careful not to over bake the biscuit).

Put the hazelnuts in a plastic bag and crush them with a pastry roll.

Roast them in the oven for 12 minutes at 180°C.

Melt the cream and add the salt.

Dry melt the caster sugar in a saucepan until it takes a nice amber colour.

Pour a small quantity of cream on the caramel, then pour the butter on top.

Bring to the boil for one minute.

Leave to cool.

Make a custard sauce with the milk, the custard, the sugar and the egg yolk. Stop after the first simmer.

Pour over the black chocolate, as previously chopped into small pieces.

Mix all.

Use lukewarm.

Whisk the cream to obtain a whipped cream.

Incorporate to the previous preparation with a spatula.

Bring the sugar, the cream and the glucose to a boil.

Pour on the milk chocolate in chips.

Mix with a whip.

Ice when lukewarm.

Spread the lukewarm caramel over the biscuit.

Add the roasted hazelnut chippings and roll the biscuit.

Store the biscuit in the freezer for 1 hour to make it firm.

Pour the chocolate mousse into a Yule log mould (plastic mould).

Insert the roll of biscuit in the chocolate mousse so that it touches the rim of the mould and smoothen the excess mousse with a spatula.

Freeze during a minimum of 24 hours.

Unmould the Yule log and ice it on a baking rack before laying it on cardboard.

Decorate according to your taste.