In a large mixing bowl, whisk together the instant vanilla pudding mix with three cups of cold milk. Follow package instructions carefully, whisking until the mixture thickens completely, which typically takes about two minutes. Set aside.

In a separate chilled bowl, pour the heavy whipping cream and add the powdered sugar and vanilla extract. Using an electric mixer on medium-high speed, beat until stiff peaks form, about 3-5 minutes.

Gently fold the whipped cream into the pudding mixture using a spatula, working carefully to maintain the airy texture and ensure even combination.

Arrange a single layer of vanilla wafers on the bottom of a 9x13-inch dish or trifle bowl, breaking cookies as needed to cover the entire bottom surface.

Spread approximately one-third of the pudding mixture over the wafer layer. Arrange half of the sliced strawberries and half of the sliced bananas evenly over the pudding.

Add another layer of vanilla wafers, followed by another third of the pudding mixture and the remaining strawberries and bananas. Ensure even distribution throughout.

Create a third layer of vanilla wafers and top with the remaining pudding mixture. Smooth the surface with a spatula to create an even, attractive top.

Cover the dish with plastic wrap and refrigerate for at least 4 hours, but preferably overnight, before serving. This allows the wafers to soften and flavors to meld.