1. Preheat the oven to 325°F 165°C. Wrap the outside of a 9 inch springform pan with two layers of heavy duty foil, lightly grease the inside, and line the bottom with a round of parchment paper.

2. Crush the chocolate sandwich cookies into fine crumbs using a food processor or by rolling them in a zip top bag. Stir the crumbs together with the melted butter and granulated sugar until evenly moistened.

3. Press the crumb mixture firmly into the bottom of the prepared springform pan, using the bottom of a measuring cup to pack it tightly into an even layer.

4. Bake the crust for 8 to 10 minutes, just until fragrant and set, then remove from the oven and let it cool slightly while you prepare the filling.

5. In a large mixing bowl, beat the softened cream cheese with the granulated sugar on medium speed until completely smooth and creamy, scraping down the sides of the bowl as needed.

6. Add the sour cream, flour or cornstarch, instant espresso powder, vanilla, and salt, then mix until everything is fully combined and the batter looks silky.

7. Pour in the Kahlua and beat just until incorporated, then add the eggs one at a time, mixing on low speed after each addition until no streaks of egg remain. Avoid overbeating at this stage.

8. Place the foil wrapped springform pan in a large roasting pan. Pour the cheesecake batter over the cooled crust and smooth the top with a spatula.

9. Carefully pour hot water into the roasting pan until it comes about halfway up the sides of the springform pan, creating a water bath.

10. Bake the cheesecake for 55 to 70 minutes, or until the edges are set and the center still has a slight wobble when the pan is gently shaken.

11. Turn off the oven, crack the door open, and let the cheesecake cool in the oven for about 1 hour to help prevent cracks from sudden temperature changes.

12. Remove the cheesecake from the water bath, discard the foil, and place the pan on a wire rack to cool completely to room temperature.

13. Once the cheesecake is at room temperature, cover the pan and refrigerate for at least 4 hours or overnight until fully chilled and set.

14. To make the ganache, place the chocolate chips in a heatproof bowl. Heat the heavy cream until steaming but not boiling, then pour it over the chocolate and let it sit for 1 minute.

15. Add the Kahlua to the chocolate and cream, then whisk until the mixture becomes smooth, glossy, and slightly thickened. Let it cool until it is pourable but not too runny.

16. Release the chilled cheesecake from the springform pan and transfer it to a serving plate. Pour the Kahlua chocolate ganache over the top, gently nudging it toward the edges so it drips down the sides.

17. Drizzle caramel sauce over the ganache or on the serving plates if desired. Slice the cheesecake with a sharp knife, wiping the blade clean between cuts for neat slices, and serve chilled.