Crush the biscuits, add melted butter and spread the mixture evenly into the base of a springform tin (or any other serving dish). Refrigerate the base for 30 minutes.
Make toffee sauce by heating butter along with brown sugar. Cook on low heat till all the sugar melts. Then add condensed milk and constantly keep stirring for 5 to 7 minutes on medium heat till you get a thick caramel sauce like consistency. Cool for 10 minutes.
Pour the toffee sauce over the biscuit base and refrigerate for 1 hour.
In a bowl whisk the chilled cream with a cake beater until you get a thick whipped cream.
Peel and slice the bananas and add 1 tsp lemon juice and mix well.
Layer the banana slices over the toffee sauce and top with the whipped cream and spread evenly. Again refrigerate for 1 hour or till the dessert is to be served.
Decorate the pie with chocolate chips, cocoa powder or chocolate sauce.
Serve chilled.