Arrange a handful of cookies in the bottom of your glass or trifle dish to create a crunchy base.
Pour a layer of smooth vanilla custard directly over the cookies, spreading gently with a spatula until even and slightly cascading over the edges.
Slice ripe bananas into thin rounds, then arrange a layer over the custard, pressing gently to keep the slices compact and neat.
Sprinkle crushed cookies over the banana layer, adding extra crunch and flavor contrast.
Repeat the layering process—adding more cookies, custard, bananas, and crushed cookies—until the dish is filled to your liking, finishing with a cookie crumb topping.
Cover the dish with plastic wrap and refrigerate for at least 2 hours, allowing the flavors to meld and the dessert to set with a creamy, soft consistency.
Before serving, optionally sprinkle a little extra crushed cookie on top for added texture and presentation.
Serve chilled, revealing the beautiful layered appearance and enjoying the contrasting textures of silky custard, tender bananas, and crunchy cookies with each spoonful.