Spray an 8-inch springform pan with parchment paper and spray with nonstick cooking spray.

In a bowl, combine shortbread crumbs and melted butter with a fork. Press the crust into the bottom of and halfway up the sides of the prepared springform pan. Set aside as you make the filling.

In a medium saucepan over low heat, melt the butter and brown sugar, stirring until the sugar has dissolved.

Add the sweetened condensed milk. Increase the temperature to medium-low, bringing the mixture to a low simmer. Stir continuously for 16-18 minutes, or until the mixture thickens and turns a golden caramel color.

Remove from heat and set aside as you make the whipped cream.

In a stand mixer with the whisk attachment, whip cream until stiff peaks are just about to form (about 1.5 minutes). Beat in confectioners' sugar until stiff peaks form.

Layer half of the banana rounds over the crust.

Pour the toffee sauce over the bananas. Add the remaining bananas.

Top with whipped cream.

Transfer the pie to the refrigerator to chill for 1 hour, up to overnight.

Serve chilled, sprinkled with extra shortbread crumbs.