Preheat your oven to 350°F (175°C). Wrap the bottom and sides of a 9-inch springform pan with heavy-duty aluminum foil to prevent water from seeping in during the water bath. Lightly spray the pan with non-stick spray and set aside. Place pecans in a food processor or blender and pulse until finely ground into crumbs. In a large bowl, combine the pecan crumbs, graham cracker crumbs, sugar, cinnamon, and salt. Add the melted butter and mix well using a rubber spatula. Press the crust mixture into the prepared pan, firmly packing it from the center and up the sides. Bake the crust for 10 minutes, then set aside to cool while preparing the cheesecake filling. Reduce the oven temperature to 325°F (160°C).

In a high-power blender, food processor, or stand mixer, beat the softened cream cheese and sour cream until completely smooth. Add the brown sugar, granulated sugar, cinnamon, and vanilla extract. Beat on medium speed until smooth, scraping the sides and bottom of the bowl as needed. Reduce the mixer speed to low and add the eggs and egg yolks, mixing until just combined. Turn off the mixer and gently fold in the bourbon and flour until just incorporated. Pour the cheesecake filling over the partially baked crust, smoothing the top with a rubber spatula. Place the cheesecake pan in a large, deep pan and fill the pan with 2 inches of hot water. This creates a water bath to help prevent cracking. Carefully place the pan in the oven and bake for 1 hour and 10 minutes. Turn off the oven and let the cheesecake sit for 30 minutes with the oven door closed. The cheesecake should still have a slight jiggle in the center. After 30 minutes, remove the cheesecake from the oven and run a knife around the edge to loosen it from the pan. Let it cool completely on a wire rack before covering and chilling in the refrigerator for at least 8 hours.

In a large skillet over low heat, melt the butter. Stir in the brown sugar and cook until the mixture is bubbling, about 2 minutes. Add the cinnamon, heavy cream, and salt, whisking to combine. Add the pecans and fold them into the liquid mixture until fully coated. Remove from heat and stir in the vanilla and bourbon (optional). Allow the topping to cool for 10 minutes before spreading it over the chilled cheesecake. Slice and serve.