Mix the Pudding: In a medium bowl, combine 1 can of condensed milk and 1.5 cups of milk. Stir well. Next, whisk in 1 small pack of instant vanilla pudding until the mixture thickens, usually about 2 minutes.
Prepare the Cream: In a separate bowl, beat 3 cups of heavy cream with an electric mixer until stiff peaks form, which will take about 3-5 minutes. Make sure to stop the mixer once you reach this texture; overbeating can turn the cream into butter!
Fold in the Cream: Gently fold the whipped heavy cream into the pudding mixture using a spatula. This process should be done delicately to maintain the airy texture of the whipped cream.
Layer the Pudding: In a large serving dish or trifle bowl, begin layering by placing a layer of vanilla wafer cookies at the bottom. Then, add a layer of 4 sliced bananas, followed by a generous portion of the pudding mixture. Repeat these layers until you've used all the ingredients, finishing with a layer of pudding on top.
Chill: Cover your dish with plastic wrap and refrigerate for at least 4 hours, or preferably overnight. This step allows the flavors to meld and gives the cookies time to soften.
Sweeten it Up: Before serving, sprinkle 2 tsp of granulated sugar evenly over the top of the pudding for a delightful touch.
Serve: Scoop out servings and enjoy the pudding chilled with your loved ones!