01 -
In large bowl, whisk together sweetened condensed milk and ice-cold water until well combined. Add vanilla pudding mix, whisking vigorously until no lumps remain. Cover and refrigerate until set, about 4 hours.
02 -
In separate large bowl, whip heavy cream until soft peaks form. Add marshmallow fluff and continue whipping until stiff peaks form.
03 -
Gently fold whipped cream into set pudding in increments, being careful not to deflate. Stir until minimal streaks remain.
04 -
In a 9x13 baking dish or large bowl, create layers: Nilla wafers, banana slices, and ⅓ of the cream mixture. Repeat for two more layers, ending with cream on top.
05 -
Decorate top with Nilla cookie crumbs if desired. Refrigerate for at least 4 more hours before serving.