To make the base first whiz the biscuits in a food processor until crumbled.
Add cocoa and melted butter and whiz until it clumps.
Put the mixture into a buttered 23cm cake tin with a removable base, and press firmly over the bottom and 2-4cm up the sides. Refrigerate while making the filling.
In a food processor whiz the cream cheese and icing sugar until smooth. Then add peanut butter, bananas and vanilla extract and whiz until smooth.
In a separate bowl beat the cream until it forms peaks.
Fold the beaten cream through the the cream cheese mixture until just incorporated.
Pour the filling into the crust, smooth the top and refrigerate overnight.
To serve add chopped banana, grated chocolate, chocolate pieces or a different topping of your choice.