Grease a loose-based 20cm cake tin.
For the base
Mix together the crumbs and butter and press into the base of the tin.
For the filling
Sprinkle the gelatine on the water in a cup and stand in hot water until dissolved.
Whisk together the cream cheese, custard and dulce de leche until blended.
Stir the gelatine into the cheese mixture and pour into the tin.
Cover with cling film and chill for 4 hours until set.
For the decoration
Decorate with fudge and grated chocolate.