Crush the cookies into fine crumbs. Mix them with the sugar and melted butter until evenly moistened
Press the mixture firmly into the bottom of a 9-inch springform pan. Refrigerate while preparing the filling
Beat the softened cream cheese until smooth. Add the dulce de leche and vanilla, then mix until creamy
In a separate bowl, whip the cold heavy cream with powdered sugar until soft to medium peaks form
Gently fold the whipped cream into the dulce de leche mixture until smooth and fluffy
Arrange the sliced bananas over the chilled cookie crust.
Spread the mousse evenly over the banana layer and smooth the top
Cover and refrigerate for at least 6 hours, preferably overnight
Whip the remaining heavy cream with powdered sugar and vanilla until medium peaks form. Spread or pipe it over the chilled cake
Gently warm the remaining dulce de leche until it is easy to drizzle. Let it cool slightly, then drizzle over the whipped cream
Add fresh banana slices just before serving
Carefully remove the springform pan. Slice with a sharp, warm knife and serve chilled
