Split the biscuits open and scrape out the cream into a mixing bowl, keep 8 cookie slices aside. Crush the remaining cookies and mix with the melted butter, line an 18 cm springform pie mould with the mixture and chill to form a pie crust. Prepare a ganache; heat up the 150 g of cream, remove from heat, whisk in the 100 g chocolate (chopped) and the rum. Pour the ganache into the pie crust and cover with the banana slices. Next put the milk on the fire together with the orange zest, vanilla and sugar. Take a couple of spoons and dilute the corn flour. Set the milk to the boil, thicken with the corn flour, cook for a couple of seconds. Remove from heat, beat in the chocolate and butter. Pour over the bananas. Allow to set and chill. Meanwhile, crush the remaining cookies and beat into the cookie cream. Whip the fresh cream with the 2 spoons of sugar and fold into the cookie cream. Use to cover and decorate the banana pie.