Preheat oven to 350°F (175°C). Grease or line an 8x8-inch baking pan with parchment paper. Note: Be sure that the parchment paper hangs over the pan so you can remove the brownies with ease after baking.
In a large microwave safe bowl, add butter and 1/2 cup chocolate chips. On 20 second intervals, melt the butter and chocolate. Using a rubber spatula, stir every 20 seconds. Once melted and you have stirred smooth, add the espresso powder and cocoa powder. Mix again until smooth.
Using a hand whisk or hand mixer, add both the sugars and mix until smooth.
Add eggs and yolk, one at a time, whisking well after each addition. Stir in the vanilla extract. Mix again vigorously until the mixture is light and glossy.
Note: we want to mix fast and vigorously at this stage so the sugar dissolves and everything is fully incorporated. To test, touch the mixture and rub it between your index finger and thumb- if it feels grainy, keep whisking.
Sift in the flour, salt and cornstarch. Mix gently with a spatula until just combined — don’t overmix.
Then gently spread batter evenly in the prepared pan. Bake for 28-33 minutes, or until the center is set and a toothpick inserted comes out with some melted chocolate and a few wet crumbs. Please note: ovens do vary- so please look at visual cues instead of time. The brownies should be pulled when the tops look a little crackly, the edges are set and the middle no longer jiggles. Depending on your oven, your brownies may need even 34 minutes- thats okay- please pay attention to visual cues.
Place brownies on a cooling rack and let them rest for about 1-2 hours.
After the brownies have completely cooled, I like to pop the pan into the freezer for about 15-20 minutes to let the brownies set up a little. This makes for an ultra rich fudge interior and easier slicing.
While you wait for the brownies to cool, work on the cheesecake layer. Place the softened cream cheese and powdered sugar in a large bowl. If the cream cheese is soft enough, you can use a hand whisk to mix them together until smooth. A hand mixer also works well.
Then add the vanilla, maple syrup, drained pumpkin puree, pumpkin spice and salt. Whisk again until everything is combined and smooth.
In a stand mixer fitted with the whisk attachment, whip the heavy whipping cream on medium-high speed (about speed 6–8 on a stand mixer) for 1–2 minutes, or until medium peaks form. The cream should hold its shape when you lift the whisk, but the tip should gently curl over rather than stand straight up. Be careful not to overwhip, we dont want the cream to look grainy or stiff. (** Note: If your cream is very cold and you're using a powerful mixer, start checking around 45 seconds. It can go from soft to medium peaks surprisingly quickly with only ½ cup.)
Then gently fold the whipped cream into the pumpkin mixture. Fold until there are no whipped cream streaks- this could take a few minutes because you want to be gentle. ** Folding too aggressively can cause the cheesecake layer to be dense. Folding gently will incorporate air and help the cheesecake layer remain nice and fluffy. Once incorporated, spread the cheesecake mixture evenly onto the brownie layer.
For the whipped cream topping, using the same bowl, add the heavy whipping cream and powdered sugar. In a stand mixer fitted with the whisk attachment, whip the heavy whipping cream on medium-high speed (about speed 6–8 on a stand mixer) for 1–2 minutes, or until medium almost stiff peaks form. Using a rubber spatula, stir in the vanilla gently. Then top the cheesecake layer with the whipped cream.
Cover the cheesecake brownies with plastic wrap (carefully) and chill in the fridge for at least 3 hours. Then remove the brownies from the pan, slice and serve.
Storage: Keep the cheesecake brownies in an airtight container in the fridge for 2-3 days.