Place the digestive biscuits, pecan nuts and dates together and blitz until finely ground. Melt the better and add to the crumbs together with the maple syrup and blitz again until you obtain a fine mixture which sticks together when pressed with your fingertips. Tightly press the biscuit base into a lightly oiled 20cm cake tin and put set for 15 minutes in a freezer. Meanwhile start preparing g the filling, place the butter and sugar over a medium heat. Cook gently until butter and sugar are dissolved, stir together to combine and add the condensed milk. Bring mixture to the boil, reduce heat and simmer for 3 minutes stirring constantly until the mixture turns deeper golden brown and smells of caramel. Remove from heat and allow to cool. Spread the caramel on top of the biscuit base, top up with the sliced bananas and whipped cream. Dust lightly with cocoa powder.