In a medium saucepan, combine 2 cups of whole milk, ½ cup of granulated sugar, 3 tablespoons of cornstarch, and ¼ teaspoon of salt. Cook over medium heat, whisking constantly for about 5-7 minutes until the mixture thickens and bubbles form.

While the milk mixture thickens, whisk 2 large egg yolks in a small bowl until smooth. Gradually add a spoonful of the hot milk mixture into the yolks while whisking vigorously to avoid curdling.

Pour the tempered egg yolk mixture back into the saucepan with the remaining pudding base. Continue to cook for an additional 2-3 minutes, stirring continuously until the mixture is thickened and glossy. Remove from heat, then stir in 2 tablespoons of unsalted butter and 1 teaspoon of vanilla extract.

In a separate mixing bowl, pour 1 cup of heavy whipping cream and add 2 tablespoons of powdered sugar. Using an electric mixer, whip the cream on high speed until stiff peaks form, about 3-5 minutes.

Begin assembling the Banana Pudding Cups by placing a layer of vanilla wafers at the bottom of each serving cup. Next, add a layer of sliced bananas, followed by a generous dollop of the creamy pudding. Repeat the layers until the cups are filled.

Top each cup with a generous helping of the whipped cream, then refrigerate for at least 1 hour before serving.