Candied chestnut yule log (bûche au marron glacé)

Bring the milk and half the sugar to a boil. Beat the yolks, cornstarch and remaining sugar, and temper the yolk mixture with the hot milk.

Return to the stove, bring the custard to a boil and cook two minutes, whisking constantly.

Off the heat, whisk in the softened gelatin and cubed butter; transfer to a tray lined with plastic wrap and cover in contact.

Loosen the chestnut paste with cognac or orange juice; with the mixer on high, beat in 20% of the custard, then the rest, until smooth and fluffy.

Fold in whipped cream and spread the chestnut mousseline evenly on the joconde sheet; cover with drained candied chestnut pieces.

Roll the log up tight in plastic wrap with a rectangle device; freeze a couple of hours to set, tighten again, wrap well and freeze at least one day.

Whip the heavy cream and incorporate the chestnut cream to make a chestnut chantilly.

Trim the ends of the frozen log and save them. Coat the log with some of the chantilly, set the saved ends on top as knots, pipe the remaining chantilly over the log and around the knots, and finish with a spatula.

Make chocolate shavings by running the back of a chef knife's blade across a chocolate bar with pressure; decorate the log.

For the joconde: beat room-temperature egg whites to soft peaks and move the meringue to another bowl; beat the almond flour, sugar, eggs and flour on high five minutes until pale yellow.

Fold 30% of the meringue into the almond mixture, then the remaining meringue, then the melted butter; the batter will deflate, which is fine.

Spread thin on an upside-down baking tray, controlling the thickness with a thumb along the edge; have the oven on at least 10 minutes beforehand.

Bake at 450F (230C) six to seven minutes, without overbaking; transfer immediately to the work surface, cool and wrap.