Whisk cold milk and pudding mix for about 2 minutes until thick and creamy. Let sit 3–5 minutes.
In a separate bowl, beat heavy cream, powdered sugar, and vanilla until stiff peaks form.
Fold whipped cream gently into pudding to create a mousse-like texture.
Slice bananas and break Biscoff cookies into large pieces for layering.
In a dish, layer pudding, cookies, bananas, caramel drizzle, and warmed Biscoff spread. Repeat until full.
Top with crushed cookies, whipped cream, and caramel drizzle. Chill 2–3 hours before serving.
