Fill a very large saucepan with water and place it over a high heat.
Once the water boils, put in the can of condensed milk and leave it to boil uncovered for 2 hours during which time the condensed milk will caramelize.
After 2 hours, carefully remove the tin from the water and leave it to cool.
Prepare the biscuit base. Put the biscuits into a food processor and blitz till the biscuits are finely crushed.
Melt the butter and add it to the crushed biscuits and mix well.
Pour the crushed biscuits into the 8”cake tin (medium sized one) and using a spatula, press it down to create an even base.
Put the tin in the fridge and chill for 15 - 20 minutes.
Prepare the bananas. Peel the bananas and chop into thin slices.
Add the bananas and toffee topping. Put the banana slice on top of the biscuit and flatten them out.
Open the tin of condensed milk, pour it over the top of the bananas and spread it over evenly. (dip the spatula in hot water to make the spreading process easy)
Refrigerate. Put the pie into the fridge for at least 20 minutes.
Whip the cream. Pour the cream into a large bowl, placed on ice. Whip the cream till stiff with an electric beater.
Add 1 tsp coffee powder to the whipped cream. Adjust it according to taste.
Top the banoffee pie with cream. Take the pie out of the fridge and spoon the whipped cream over the top.
Refrigerate again. Put the banoffee pie back into the fridge and leave to chill for a further 20 minutes.
Sprinkle coffee powder or cocoa powder on the banoffee pie.
Open the seal of the cake tin, run a knife around the inside and finally, remove the tin completely and serve. (dip the knife in hot water to make the spreading process easy)