Crust: Mix crushed vanilla wafers, sugar, and melted butter. Press into a greased springform pan and bake for 8-10 minutes at 350°F (175°C).
Cheesecake Filling: Beat cream cheese and sugar until smooth. Add mashed bananas, eggs, vanilla extract, and sour cream. Mix until combined.
Banana Pudding Layer: Whisk instant vanilla pudding mix with cold milk until thickened. Fold in whipped cream. Layer sliced bananas over crust, then spread half of the pudding mixture.
Assembly: Pour half of the cheesecake filling over the crust. Layer remaining bananas and pudding mixture. Top with the rest of the cheesecake filling.
Bake: Bake cheesecake for 55-60 minutes at 350°F (175°C), until set in the center and lightly golden on the edges.
Cool: Allow the cheesecake to cool in the oven with the door cracked open for about 1 hour. Refrigerate for at least 4 hours until fully chilled and set.
Garnish and Serve: Remove from springform pan, garnish with whipped cream, banana slices, and crushed vanilla wafers. Slice and serve chilled.