• Slice two of the bananas into ¼ or so thick coins.  Place the banana slices into the bottom of the prepared pie crust and sprinkle with 1 teaspoon of cinnamon.

For the custard filling

• Whisk together 4 egg yolks and 3 tablespoon cornstarch in a small bowl and set aside.
• In a large saucepan, combine the milk, heavy cream, sugar, and salt.  Heat over medium low for about 5 minutes or just until you can begin to see steam and very gentle bubbles around the edges.  Do not let it come to a full boil.
• Pour a splash of hot milk mixture into the egg yolk mix.  Whisk quickly to combine.
• Add another larger splash of the milk mix to the yolk mixture, continuing to whisk quickly. 
• Pour the entire egg mixture into the saucepan and continue to whisk.
• Heat over medium low for an additional 2-3 minutes or until thickened.  Continue to mix constantly to prevent scorching. 
• Add in 2 tablespoon butter and 2 teaspoon vanilla and continue to mix until melted and thoroughly combined.
• Pour the custard over the banana slices in the pie crust.
• Cover tightly with plastic wrap, allowing the plastic wrap to touch the top of the custard to prevent a film from forming. Chill for 4 - 8 hours until set.

For the topping

• Combine 1 cup heavy cream, 2 tablespoon powdered sugar and ½ teaspoon vanilla.  Mix on medium high speed for about 3-5 minutes or until stiff peaks.
• Transfer the whipped topping to a piping bag fitted with a large star tip.
• Pipe small mounds across the top of the pie.
• Slice the remaining bananas into slices and place on top of the whipped cream.