For the cookie crust, place the cookies in a plastic bag and beat them with a kitchen hammer or a rolling pin until you turn them into small cookie crumbs. Add butter and egg white and mix well until you get a sticky dough.
Prepare a round 18 cm baking tray and cover it with baking paper. Transfer the cookie dough in the baking tray and press it down evenly. Bake at 180 degrees Celsius for 8 - 10 minutes. Let cool completely and remove from the baking tray on a serving plate. Place the round cake form back around the crust to keep the puree and mousse in place.
Cook the pears, apple-pear puree and vanilla on medium heat until very soft. The fruit should start to dissolve and you can help it a little with a hand stick mixer. Mix in the gelatin powder and let it cool a little before you spread it evenly over the cookie crust. Place in the fridge while you make the chocolate mousse.
Melt the chocolate and butter over a water bath. Set aside and let cool a little.
In a medium bowl, whisk the whipping cream until soft peaks form. In a separate bowl whisk the eggs and honey until foamy, then add the rum and mix well.
Carefully mix the gelatin in the chocolate mixture to prevent any lumps from forming.
Pour the melted chocolate in the egg mixture and top it with whipped cream. Fold carefully to prevent losing too much air. Once completely mixed, add walnuts and mix well.
Pour the chocolate mousse in the cake form and spread evenly. Place in the fridge over night and decorate in the morning.