Start by prebaking your pie crust using the directions on the package and set it aside to cool.
Add the milk, sugar, cornstarch, salt, egg, and egg yolk to a large saucepan and whisk until combined.
Turn on medium heat and stir constantly until it starts to simmer and thicken. Remove it from the heat and whisk in the butter and vanilla.
Wrap the top with plastic wrap directly over the pudding, making sure the plastic touches the pudding so it doesn't form a skin on the top. Be careful the pan will be hot. Let the saucepan with pudding cool on the counter for 30 minutes.
Place the sliced bananas onto the bottom of the crust.
Then spread the pudding over the bananas and cover the pie with plastic wrap and make sure it touches so it doesn't form a skin.
Place the pie in the fridge for 3-4 hours or until the pudding sets.
Add the heavy cream, powdered sugar, and vanilla to a medium mixing bowl and whip until it starts to form stiff peaks. Spread the whipped cream over the pie and then slice, serve and enjoy.