In a large saucepan, melt 100g of butter and stir in the crushed
biscuit. Press into the base and about halfway up the sides of a 19cm loose-bottomed cake tin to make a pie shell. Place in the fridge to chill while preparing the caramel.
To make the caramel, place the butter and the sugar in a non-stick saucepan over a low heat stirring all the time, until the butter melts and the sugar dissolves. Add Bonny Sweetened Condensed Milk and stir continuously. Bring gently to a boil to make a smooth and thick golden caramel. Spread the caramel over the biscuit base and chill for about 1 1/2 hours, until firm or ready to serve.
Carefully lift the pie from the tin and place on a serving plate. Slice the bananas and arrange a few pieces over the caramel. Spread with cream. Decorate with the remaining pieces of banana and dust liberally with cocoa powder.