Preheat oven to 325°F (163°C). Mix crushed vanilla wafers, melted butter, sugar, and salt; press into a springform pan. Bake 10 minutes and cool.
Beat cream cheese until smooth. Add sugar, sour cream, vanilla, banana extract, and mashed bananas. Mix in eggs one at a time on low speed.
Wrap pan in foil and place in a water bath. Pour batter over crust and bake 55–65 minutes until edges set and center jiggles slightly.
Let cheesecake rest in oven 1 hour, then cool completely on a wire rack. Refrigerate at least 6 hours or overnight.
Whisk pudding mix with milk until thickened, fold in whipped topping, and spread over chilled cheesecake. Chill 1 hour.
Top with banana slices, whipped cream, and crushed or whole vanilla wafers before serving.