In a medium saucepan, combine the whole milk, sweetened condensed milk, and vanilla extract. Heat over medium heat, stirring occasionally until the mixture is warm but not boiling. Remove from heat and let it cool slightly.
In a large mixing bowl, whip the heavy cream and powdered sugar together until stiff peaks form.
Gently fold the whipped cream into the cooled milk mixture until well combined.
In a 3-quart dish or a large trifle bowl, layer half of the vanilla wafers on the bottom.
Add half of the sliced bananas on top of the wafers.
Pour half of the pudding mixture over the bananas.
Repeat the layers with the remaining wafers, bananas, and pudding mixture.
Cover the dish with plastic wrap and refrigerate for at least 4 hours or overnight to allow the flavors to meld and the wafers to soften.
Serve chilled, and enjoy!