To make the brownies:

1. To make the brownie, preheat oven to 350°F (176°C). Grease a 9×13-inch baking pan.
2. Combine the butter, sugar and vanilla extract in a medium sized bowl. Add eggs and mix until well combined.
3. Combine flour, cocoa, baking powder and salt in another medium sized bowl, then add the dry ingredients to the egg mixture until well combined.
4. Pour the batter into the pan and spread evenly. Bake for 22-26 minutes, or until a toothpick comes out with a few moist crumbs.
5. Set aside to cool completely.

To make the crust:

6. Preheat oven to 325°F (163°C). Line a 9-inch (23cm) springform pan with parchment paper in the bottom and grease the sides.
7. Combine the crust ingredients in a small bowl. Press the mixture into the bottom of the springform pan.
8. Bake the crust for 10 minutes, then set aside to cool.
9. Cover the outsides of the pan with aluminum foil (I also use a plastic crock pot liner – see method in this tutorial) so that water from the water bath cannot get in. Set prepared pan aside.

To make the cheesecake filling and topping:

10. Reduce oven to 300°F (148°C).
11. In a large mixer bowl, mix the cream cheese, sugar and flour until well combined (Use low speed to keep less air from getting into the batter, which can cause cracks). Scrape down the sides of the bowl.
12. Add the pumpkin, sour cream, vanilla extract and spices and mix on low speed until well combined.
13. Add the eggs one at a time, beating slowly and scraping the sides of the bowl after each addition. Set mixture aside.
14. Cut the cooled brownies into smaller squares, about 1 inch or so in size.
15. Place some brownies into the crust of the cheesecake, spacing them evenly. I used 12 brownies, but you could add more if you want a more heavily brownie-filled filling. Just don’t add too many or you won’t have room in your pan for all the cheesecake filling.
16. Gently spoon the cheesecake filling evenly into the crust and over the brownies, trying not to displace the brownies.
17. Place springform pan (covered with aluminum foil) inside another larger pan. Fill the larger pan with enough warm water to go about halfway up the sides of the springform pan. The water should not go above the top edge of the aluminum foil on the springform pan.
18. Bake for 1 hour and 20 minutes. The edges of the cheesecake should be set and center should be somewhat set but still jiggly.
19. Turn off the oven and leave the cheesecake in oven with the door closed for 30 minutes.
20. Crack oven door and leave the cheesecake in the oven for another 30 minutes.
21. Remove the cheesecake from the oven and water bath wrapping and refrigerate until firm, 5-6 hours or overnight.
22. When the cheesecake is cool and firm, remove from the springform pan and set on a serving plate.
23. Pile the remaining brownies onto the top of the cheesecake. You may not need to use them all. Set cheesecake aside to make the fudge topping.
24. To make the fudge topping, place the chocolate chips in a small heat proof bowl.
25. Heat the heavy whipping in a glass measuring cup heat just until it begins to boil.
26. Pour the hot liquid over the chocolate chips and allow to sit for 2-3 minutes, then whisk until smooth.
27. Drip the chocolate ganache around the edge of the cheesecake, then drizzle more on top of the brownies.
28. Serve the cheesecake while the chocolate is still warm or refrigerate until ready to serve. Cheesecake is best stored in the fridge well covered and eaten within 4-5 days.