How to Bake Banana into Banoffee Pie
My recipe, from the originators' Nigel Mackenzie and Ian Dowding cookbook, The Deeper Secrets of the Hungry Monk, has the bananas sliced, arranged over crust, and the caramel poured over the bananas. The only part that is cooked is the sweetened condensed milk and butter, boiled down to make the caramel.

Since we don't do recipes on SE, I've given you the Wikibooks link which has the full ingredients and directions.