In a large bowl whisk together milk and instant pudding for 2 minutes until thick. (Do not follow instructions on back of pudding box. Follow these instructions for a thicker texture to hold up in the pie.)
optional: add 1 tsp vanilla to cool whip and mix well to combine.
Fold in 3 cups or 1 1/2 cartons of cool whip until well combined.
Pour half of the mixture in the prepared graham cracker crust and smooth out.
Layer banana slices on top of mixture.
Pour rest of mixture onto bananas. Layer banana slices onto mixture.
Top with remaining 1/2 carton or 4oz of cool whip. Garnish with additional banana slices.
Refrigerate for 3-4 hours to set up. Enjoy.
