This is the ultimate hybrid: a combination of banana and toffee in once incredible pie.
Technique tip: The crust and toffee sauce can be prepared up to 4 hours ahead, covered separately. Refrigerate the crust and keep the sauce at room temperature.
For the crust:1.
Line the bottom of a 9-inch springform pan with parchment paper.2.
Chop the graham crackers in a food processor until they are finely ground. Pour 8 tablespoons of the melted butter over the crumbs and process to blend well. Add enough of the remaining 2 tablespoons butter to form a crumb mixture that sticks together when pressed.3.
Press the crumb mixture over the bottom and 1½ inches up the sides of the springform pan. Refrigerate.
For the toffee sauce:1.
Combine the brown sugar and 3 tablespoons water in a medium-size heavy saucepan. Stir over medium heat until the sugar dissolves. Raise the heat and boil without stirring, occasionally swirling the pan and brushing down the sides with a pastry brush dipped into water, until the syrup is a deep amber color, about 5 minutes.2.
Stir in the condensed milk and butter. Continue stirring for 5 minutes or until the sauce thickens slightly.3.
Remove the toffee sauce from the heat, and spread 1 cup of the sauce over the prepared crust. Refrigerate for about 1 hour or until the toffee is semi-firm. Keep the remaining toffee sauce at room temperature.
For the filling:1.
Using an electric mixer, beat the cream in a large bowl until thick and very soft billowy peaks form.2.
Slice 3 of the bananas into very thin discs. Fold the sliced bananas into the softly whipped cream, and spoon the filling into the prepared pie crust. Slice the remaining 2 bananas, and arrange the slices decoratively over the pie.3.
Rewarm the remaining toffee sauce gently over low heat. Drizzle some of the sauce decoratively over the pie (if the sauce has thickened too much to drizzle, stir a few tablespoons of milk into it).
Cut the pie into wedges, and transfer them to plates. Drizzle each pie wedge with more sauce, and serve.