CRUST: Process biscuits in a food processor into fine crumbs. Add oil and enough milk for crumbs to come together, but not to be soggy, and process again. Transfer into a pie pan. Press crumbs firmly into the bottom of the pan.

FILLING: In a saucepan, melt sugar until lightly caramelized*. Add cream while standing away from the pot (the cream will make the caramel steam a lot). Cook, stirring, until caramel melts and mixture thickens. Remove from heat and let cool to room temperature.

TO ASSEMBLE: Split bananas lengthwise and dip them in lemon juice (this will prevent bananas from turning brown).

Pour half of the caramel filling into pie crust. Arrange banana slices over toffee. Top with remaining filling. Refrigerate until filling thickens, about 30 minutes.

Top with whipped cream and sprinkle with grated chocolate.