Step 1: Prepare the Crust

1. Preheat the oven to 325°F (163°C). Grease a 9-inch springform pan and line the bottom with parchment paper.
2. In a bowl, mix the chocolate cookie crumbs, melted butter, and sugar until well combined.
3. Press the mixture firmly into the bottom of the springform pan.
4. Bake for 10 minutes, then set aside to cool.

Step 2: Make the Cheesecake Filling

1. In a large mixing bowl, beat the softened cream cheese until smooth.
2. Add the granulated sugar and brown sugar, mixing until fully incorporated.
3. Mix in the mashed bananas and vanilla extract.
4. Add eggs one at a time, beating on low speed after each addition.
5. Stir in the sour cream and flour, mixing until just combined.

Step 3: Bake the Cheesecake

1. Pour the cheesecake filling over the cooled crust, smoothing the top.
2. Wrap the bottom of the pan with aluminum foil and place it in a larger baking dish filled with an inch of hot water.
3. Bake for 60-70 minutes until the edges are set but the center is slightly jiggly.
4. Turn off the oven, crack the oven door slightly, and let the cheesecake cool inside for 1 hour.
5. Remove from the oven and refrigerate for at least 6 hours or overnight.

Step 4: Make the Caramel Sauce

1. In a saucepan over medium heat, melt the sugar, stirring constantly.
2. Once the sugar turns amber in color, carefully add the butter, stirring until melted.
3. Slowly pour in the heavy cream, whisking continuously.
4. Let the caramel simmer for 1-2 minutes until smooth. Remove from heat and stir in the sea salt if using.
5. Allow the caramel to cool slightly before using.

Step 5: Assemble and Serve

1. Once the cheesecake is fully chilled, remove it from the pan and place it on a serving plate.
2. Pour the caramel sauce over the top, allowing it to drip down the sides.
3. Arrange banana slices on top and sprinkle with chopped nuts.
4. Drizzle extra caramel for an elegant finish.
5. Slice and enjoy!