Prepare cake according to package directions for a 9x13-inch baking dish.
Once it comes out of the oven (while still warm), poke several holes all over the top of the cake using the handle of a wooden spoon or something similar (the holes should be large enough for the caramel sauce to go into.)
Pour caramel sauce evenly over cake making sure the caramel sauce gets into the holes.
Spread sauce around and into the holes (using an offset spatula or a butter knife).
Allow the cake to cool completely. Once cake has cooled, top with sliced bananas.
In a medium bowl, combine instant banana cream pudding with 1 cup milk. Whisk until smooth and starting to thicken.
Then add in Cool Whip. Stir together gently until combined.
Then spread topping on top of banana layer.
Place Biscoff cookies in a Ziploc bag and crush them up using a rolling pin or other heavy object.
Then sprinkle cookie crumbs all over the top of the cake. Slice and serve.
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Notes
If you'd like, drizzle some caramel sauce over the individual servings.
Be sure to refrigerate leftovers.
Add about a teaspoon of rum or rum extract to the pudding topping for more of that true Bananas Foster flavor.