Prepare 9" springform pan by lining bottom with a 9 inch parchment round.
To make the chocolate graham crumbs, pulse in food processor until you only see fine crumbs, about 1 minute.
Thoroughly combine crumbs and melted butter. Press an even layer firmly into bottom of pan.
To make the cheesecake filling:
Start by microwaving the chocolate chips on 50% power, just until melted. Start with one minute, stir, and then continue 30 seconds at a time until melted when stirred. Set aside and allow to cool to room temperature. You want it to be soft enough to mix but not hot enough to cook the batter when you mix it.
In a stand mixer bowl, beat cream cheese on medium high speed with the paddle attachment until completely smooth and fluffy, scraping occasionally, about 3 minutes.
Add the sugar and cream mixture until well combined. Scrape again.
Add the pumpkin, mix well, and scrape again.
Add whole eggs and egg yolks. Mix on low until combined. Scrape again.
In a separate bowl mix cornstarch, heavy cream, lemon juice, and pumpkin pie spice. Stir very well to get any and all cornstarch lumps out. Combine well with the cream cheese mixture.
Pour all but about 1 cup of cheesecake mixture onto the crust. Stir melted chocolate into the remaining cheesecake mixture. Spoon large dots of the chocolate mixture on top of cheesecake batter. Use a butter knife to create a swirl design between the chocolate and the pumpkin cheesecake batter.
To bake cheesecake:
Preheat oven to 350 degrees F.
Bake at 350 degrees F for 10 minutes. Reduce heat to 275 degrees F and bake and additional 60-70 minutes. Time will vary depending on your oven. Center should be only slightly jiggly.
Chill overnight before removing from springform pan.