1. Prepare the pan and oven by preheating to 325°F (160°C), lining the bottom of a 9-inch springform pan with parchment, lightly greasing the sides, and wrapping the outside in a double layer of heavy-duty foil for a water bath.

2. Make the graham cracker crust by combining graham cracker crumbs, granulated sugar, melted butter, and salt in a bowl and stirring until the mixture resembles damp sand and holds together when pressed.

3. Press the crust mixture firmly into the bottom of the prepared springform pan in an even layer, then par-bake for 8–10 minutes until fragrant and just set; remove from the oven and let cool slightly.

4. Mash the ripe bananas in a small bowl until mostly smooth, then stir in the lemon juice to keep the bananas from browning and to brighten their flavor.

5. Beat the softened cream cheese in a large mixing bowl until completely smooth, then add the granulated sugar and beat again until light and creamy, scraping down the bowl as needed.

6. Add the sour cream, mashed bananas with lemon juice, vanilla extract, and cornstarch to the cream cheese mixture and mix on low speed just until everything is evenly combined and the batter looks smooth.

7. Add the eggs one at a time, mixing on low speed after each addition just until incorporated, being careful not to over-mix so you do not add too much air to the batter.

8. Pour the cheesecake batter over the warm crust in the springform pan, smooth the top, place the pan in a larger roasting pan, and pour hot tap water into the roasting pan until it reaches halfway up the sides of the springform pan.

9. Bake the cheesecake at 325°F (160°C) for 55–70 minutes, or until the edges are set and the center jiggles slightly when the pan is gently shaken, then turn off the oven and crack the door open.

10. Cool the cheesecake in the turned-off oven with the door cracked for 45–60 minutes, then remove it from the water bath, place the pan on a cooling rack, and allow it to come to room temperature.

11. Chill the cheesecake, covered, in the refrigerator for at least 4 hours or overnight until thoroughly cold and firm before adding the topping.

12. Whip the banana cream topping by beating the cold heavy whipping cream and powdered sugar in a chilled bowl until soft peaks form, then sprinkling in the instant banana cream pudding mix and whipping until thick, fluffy, and able to hold soft peaks; whisk in the cold milk a little at a time if the mixture seems too thick.

13. Top the chilled cheesecake by removing the springform ring, transferring the cheesecake to a serving plate if desired, and spreading the banana cream topping over the surface in soft swoops.

14. Garnish just before serving with sliced bananas and a sprinkle of crushed vanilla wafer cookies or extra graham cracker crumbs, then slice with a hot, clean knife for neat pieces and serve well-chilled.