Preheat oven to 350°F and prepare a water bath for your 8" x 8" baking pan (if using. See note below). Line baking pan with parchment or foil leaving an overhang on all sides. Set aside.
For the crust:
Place cookies into bowl of food processor and finely process. Add sugar and melted butter and process until mixture resembles fine sand. Dump into baking pan and evenly press crumb mixture into pan to form crust. Place in refrigerator to set while preparing cheesecake.
Place cream cheese and sugar in a large bowl. Beat on medium high speed until smooth. Add vanilla, eggs and sour cream and beat until combined. Remove 1 ¾ cups batter from bowl and evenly spread over crust.
24 ounces cream cheese,, ¾ cup sugar, 1 teaspoon vanilla extract, 2 eggs, ¼ cup sour cream
Add pumpkin puree and spices to the remaining batter and stir until thoroughly combined. Carefully spread pumpkin layer over cheesecake layer in baking pan.
Place baking pan in water bath in the oven and bake for 55-60 minutes. Turn off the oven, prop the oven door open with the handle of a wooden spoon and allow to cool for another hour.
Remove bar pan from water bath and refrigerate for at least 4 hours.
When ready to serve, lift bars from pan using overlapping parchment or foil. Cut cleanly using a clean, warm knife (run under hot water and dried). Sprinkle bars with chopped chocolate, if desired.
2 ounces dark chocolate,
Always start with room temperature ingredients. Cream cheese blends much more smoothly when it's not chilled.
Line the pan with parchment paper or nonstick foil to use as handles to lift the cheesecake bars out of the pan when you’re ready to cut and serve them.
Chocolate wafer cookies give these bars an eye-catching crust but they can be hard to find sometimes. You can easily substitute chocolate sandwich cookies for a similar look or use graham crackers or gingersnaps instead.
Use the bottom of a drinking glass or measuring cup to press the cookie mixture into the pan to keep the crust even.
A simple water bath is the best way to prevent your cheesecake from cracking and ensure even baking (see instructions below).
Chill the cooled cheesecake for at least 8 hours before slicing.
This recipe can be made up to 3 days in advance. Store covered in refrigerator until ready to serve.
To make the cleanest slices, run a sharp knife under hot water. Dry the knife with a towel and make one cut in the bars. Rinse knife and repeat process until all cuts have been made.
How to make a water bath:
Place a 9x13" pan in the preheated oven. Put your 8x8" pan of unbaked bars inside the 9x13" pan and fill the 9x13" with hot water until the bottom half of the 8x8" pan is covered with water. Bake as directed.