In a large bowl, combine the cold milk and dulce de leche, mixing until slightly clumpy.

Sprinkle the instant vanilla pudding mix over the top and whisk until smooth, which should take about 2-3 minutes. A hand whisk is preferred to avoid clumping.

Allow the mixture to sit for 5-10 minutes to thicken.

While the pudding thickens, prepare the whipped cream. In a stand mixer or using an electric hand mixer, beat the heavy cream and vanilla extract until stiff peaks form. If overbeaten, add a splash more cream and beat until stiff peaks return.

Gently fold the whipped cream into the pudding mixture using a rubber spatula. Set aside in the refrigerator for 1 hour.

To assemble the dessert, you can use individual cups, a large casserole dish, or a trifle bowl. Start with a layer of pudding at the bottom, followed by a layer of whole cookies, and then a layer of sliced bananas.

Repeat the layering process until you run out of ingredients, aiming for 2-3 layers in total.

Finish with a final layer of pudding that completely covers the top, ensuring the edges are sealed to prevent the cookies from drying out.

Cover gently with plastic wrap and refrigerate for at least 6 hours, or up to 24 hours, to allow the flavors to meld and the cookies to soften.

For the topping, crush any leftover cookies into larger pieces and sprinkle them over the top. Garnish with additional banana slices.