Preheat oven to 325°F (165°C)
Mix vanilla wafer crumbs, melted butter, and sugar
Press firmly into the bottom of a springform pan
Bake crust for 10 minutes, then cool completely
Beat cream cheese until smooth
Add sugar and mix until combined
Add eggs one at a time, mixing on low speed
Mix in mashed bananas and vanilla
Fold in sour cream and heavy cream
Whisk pudding mix with cold milk until thick
Pour cheesecake filling over cooled crust
Spoon pudding evenly over the cheesecake layer
Smooth the top gently
Bake for 60–70 minutes until edges are set and center slightly jiggles
Turn off oven, crack door, and cool cheesecake inside for 1 hour
Refrigerate at least 4 hours or overnight
Top with whipped cream, banana slices, and crushed wafers before serving