1. make the base by crushing the biscuits and mixing with melted butter, then spread over the base and sides of your tin. 2. Make the toffee filling by melting butter and sugar, then adding condensed milk and boiling until thickened. 3. Pour the toffee mixture onto the biscuit base and leave to cool and set. 4. Slice the banana and place on top of the cold toffee mixture. 5. Whip the double cream and spread on top of the bananas, then sprinkle with grated chocolate or cocoa. 6. Remove from the tin and allow to cool in the fridge for an hour before serving.