Pre-heat the oven to 180 degrees celsius. Cream together the butter, sugar, vanilla essence and 10 tbsp of condensed milk until the mixture is fluffy. Sift the flour and baking powder into the cream mix. Mix in the chocolate chips.
Separate the mixture into 4 and roll each into rectangles. Place on a greased baking sheet and cook for 20 minutes. Allow to cool. Blitz the bananas with the Snickers and the remaining condensed milk. Fold through the vanilla ice-cream.
Smear the ice-cream mixture on to the cookie slabs and pile them up to create a stack. Pour the melted chocolate over the top and serve.