Put tin of sweetened condensed milk in a pan of boiling water, then simmer for between 3 or 5 hrs depending how caramelised you want it.
Well you can if you want, but you will find this method a lot easier;
200gr pack of biscuits, (digestives are best)
Tin of condensed milk
Put the biscuits in a freezer bag then smash to crumbs with a rolling pin, put the crushed biscuits into a bowl and pour 100gr of melted butter over and mix well.
push the biscuit /butter mix into the bottom of a cake tin, then put in the fridge to set.
Pour tin of condensed milk in to a saucepan.
Along with the butter 150gr and 175 gr f sugar.
Bring to the boil, stirring constantly, till its caramelised, 5 to 7 mins, your better off under cooking than over, getting this right is a bit of trial and error.
Cut up two of the bananas and place on the chilled biscuit base.
Let the caramelised milk cool slightly then pour over the bananas. once its cool place in the fridge to set.
That is the basic pie, use the extra banana and cream to decorate, try using melted chocolate, I saw a recipe that used cream in the bottom with coffee sprinkled onto it, as I try different ideas I will post the results, if you have any ideas, let me know how they turn out.