Preheat the oven to 350°F (175°C).
Place the Biscoff cookies in a food processor or blender and pulse until they form fine crumbs.
Drizzle the melted butter over the crumbs and pulse a few times until the crumbs are evenly coated.
Press the crumb mixture into the bottom and up the sides of a 9- or 9½-inch pie pan to form a crust.
Bake the crust for 10 minutes, then remove and let it cool completely.
Arrange the sliced banana discs in a single layer on the cooled crust.
Whisk the two packages of instant banana cream pudding with 2 cups of cold milk until smooth and thickened.
In a separate bowl, beat 1½ cups heavy whipping cream with 3 tablespoons powdered sugar until stiff peaks form.
Fold ½ cup of the whipped cream into the pudding mixture until fully combined to lighten the filling.
Pour the pudding mixture over the banana-lined crust and spread into an even layer. Chill the pie for 3 hours to set.
Before serving, top the pie with the remaining whipped cream and, if desired, sprinkle extra Biscoff cookie crumbs over the top.