Submerge the gelatine in a bowl of cold water and set aside. Next, make the caramel by placing the sugar in a medium saucepan over med/high heat. In a separate saucepan heat the cream. Stir the sugar until it has melted then stop stirring and watch it closely. You want it to be a dark amber colour or 165°C. Once it reaches the desired colour, remove from the heat and gradually add the hot cream. Be careful as it will bubble and spit! Keep stirring until the caramel is smooth. If there are lumps of caramel, place back on the heat and whisk continuously until you have a nice glossy mixture. Next add the gelatine. Make sure you squeeze and discard the liquid before adding it. finally, stir in the salt. Set aside to cool to room temperature.
While the caramel is cooling, prepare the egg yolk meringue (yes, egg yolk!! this isn’t an error) by placing the egg yolks in the bowl of your mixer. Next, make your sugar syrup by heating the sugar and water over med/high heat until it reaches 118°C. While the sugar syrup is heating, start beating the egg yolks then when the syrup is ready slowly pour it in as you continue to beat. Keep beating until the mixture cools to room temperature.
Make the whipped cream by beating the cold cream until soft peaks form. Using a spatula, mix 1/3 of the whipped cream into the cooled caramel. Once completely incorporated, gently fold the caramel into the meringue mixture, followed by the rest of the whipped cream.
Pour the mousse into your Yule log mould. Remove the passionfruit insert from the freezer and place into the centre of the mould. Cover with more mousse then add the mudcake with the peanut croustillant layer facing down. Place in the freezer overnight.