Crush the biscuits with the butter and the sherry and place as a base in a springform tin. Bake this base for 4 minutes at 160/180º.
On the other hand, mix the rest of the ingredients and pour them on top of the biscuit base. Bake in the oven, not too hot at 160/180º, for 1 hour and 45 minutes.
When cool, remove from the mould and decorate with liquid caramel and chestnuts in syrup.