Prepare the Pudding: In a medium bowl, whisk together the sweetened condensed milk and ice-cold water. Add the instant vanilla pudding mix and whisk for about 2 minutes until the pudding thickens. Let the pudding sit for 5 minutes to set.

Whip the Cream: In a separate large bowl, beat the heavy cream with an electric mixer on high speed until stiff peaks form, about 3-5 minutes.

Fold the Pudding and Whipped Cream Together: Gently fold the prepared pudding mixture into the whipped cream. Be careful not to deflate the whipped cream too much; you want to keep the mixture light and fluffy.

Assemble the Banana Pudding: In a large glass trifle dish or serving bowl, layer the ingredients. Start by placing a layer of vanilla wafers at the bottom, followed by a layer of sliced bananas. Spread a layer of the pudding mixture over the bananas and wafers. Repeat the layers until all ingredients are used, ending with a final layer of the pudding mixture on top.

Chill the Pudding: Cover the banana pudding with plastic wrap and refrigerate for at least 4 hours, preferably overnight, to allow the flavors to meld and the wafers to soften.

Serve: Garnish with extra vanilla wafers and banana slices before serving, if desired. Scoop and enjoy!