You will need a 20cm (8in) round, spring-form tin with deep
sides, and a piping bag (optional). Line the sides of the tin
with strips of cling film (using a little water to help the cling
film stick) and then line the base with a disc of baking paper.
First make the pie base. Place the biscuits in a freezer bag
and finely crush with a rolling pin. Melt the butter in a
non-stick saucepan over a low heat, add the biscuits and
combine. Spoon into the base of the tin, pressing down with
the back of the spoon to level. Chill for 15 minutes.
To make the filling, heat the butter and sugar in the same
pan and stir over a low heat until combined. Add the
condensed milk and bring to the boil and boil, stirring
continuously, for 2–3 minutes or until dark golden, taking
care that the mixture doesn’t catch on the bottom. Do not
allow to boil for too long or it will become grainy. Add the
vanilla extract and pour into the tin. Chill in the fridge for
a minimum of 1 hour or up to 24 hours.
Peel and slice the bananas and arrange in neat rounds on top
of the caramel. Whip the cream to soft peaks and spoon or
pipe it over the bananas, then level the top before chilling in
the fridge for an hour.
Meanwhile, melt the chocolate in a bowl set over pan of gently
simmering water. Remove from the heat and allow to cool.
Remove the edges of the tin from the banoffee pie, peel off
the cling film and transfer to a serving plate, slipping the
baking paper from underneath. Zigzag the melted chocolate
over the top (if using), making sure it’s cool or it will melt the
cream, or dust with cocoa powder.