Step 1: In a medium saucepan, whisk together 1 cup of granulated sugar, cornstarch, and salt.
Step 2: Gradually whisk in the whole milk and egg yolks until smooth.
Step 3: Cook over medium heat, stirring constantly with a whisk, until the mixture thickens and comes to a gentle boil. Continue to boil for 1 minute, stirring.
Step 4: Remove from heat and stir in the butter and 1 teaspoon of vanilla extract until melted and combined.
Step 5: Cover the surface of the custard directly with plastic wrap to prevent a skin from forming, and let it cool slightly at room temperature while you prepare the whipped cream.
Step 6: In a large mixing bowl, beat the cold heavy cream, powdered sugar, and the remaining 1 teaspoon of vanilla extract with an electric mixer on medium-high speed until stiff peaks form.
Step 7: Gently fold about half of the whipped cream into the cooled custard until just combined. Reserve the remaining whipped cream for topping.
Step 8: Arrange a single layer of vanilla wafers on the bottom of a 9x13 inch baking dish or a large trifle bowl.
Step 9: Top the wafers with an even layer of sliced ripe bananas.
Step 10: Spoon about half of the custard mixture over the bananas, spreading it gently to cover.
Step 11: Repeat with another layer of vanilla wafers, then bananas, and finally the remaining custard.
Step 12: Spread the reserved whipped cream evenly over the top layer of custard. Optionally, arrange a few more vanilla wafers or banana slices on top just before serving.
Step 13: Cover the dish tightly with plastic wrap and refrigerate for at least 4-6 hours, or preferably overnight. This allows the flavors to meld and the wafers to soften.
Step 14: Serve chilled and enjoy your delightful Banana Pudding Recipe!