01 - Whisk together cold milk and instant vanilla pudding mix in a large mixing bowl for 2 minutes. Let stand for 5 minutes to thicken.
02 - Stir in the sweetened condensed milk until fully incorporated into the pudding mixture.
03 - In a separate bowl, whip 1 cup heavy cream to soft peaks. Gently fold the whipped cream and vanilla extract into the pudding base until smooth and uniform.
04 - Arrange a single layer of Biscoff cookies in the bottom of a trifle dish or 9x13-inch baking dish.
05 - Top the cookie layer with half of the banana slices, followed by half of the pudding mixture.
06 - Create a second layer with the remaining Biscoff cookies, banana slices, and pudding mixture, ending with pudding on top.
07 - Cover the dish and refrigerate for at least 4 hours, or preferably overnight, to allow flavors to meld and cookies to soften to a cake-like texture.
08 - Before serving, whip the remaining 1 cup heavy cream with powdered sugar and 1/2 teaspoon vanilla extract until stiff peaks form.
09 - Spread or pipe the whipped cream over the chilled pudding surface. Garnish generously with crushed Biscoff cookies and additional banana slices if desired. Serve cold.