• Gather all ingredients and equipment before beginning.

For the Crust:

• Preheat the oven to 350°F. Place about 30 chocolate wafers in a food processor and pulse until they form fine crumbs.
• With the processor running, slowly pour in the melted butter until the crumbs are evenly moistened and begin to clump.
• Prepare a 9-inch springform pan by spraying the bottom and sides, lining the bottom with a round piece of parchment and a strip around the sides, then spraying the parchment.
• Press the crumb mixture firmly into the bottom and slightly up the sides of the pan to form an even crust. Bake 10 minutes, then remove and let cool while you prepare the filling.

For the Filling:

• Lower the oven temperature to 325°F and bring a kettle or pot of water to a boil for the water bath you'll use later.
• In a stand mixer fitted with the paddle (or using a hand mixer), beat the room-temperature cream cheese until fully smooth and free of lumps for a silky base.
• Stir the mixture gently with a spatula to release any trapped air; reducing air helps prevent cracks while baking.
• Add the granulated sugar, cornstarch, kosher salt, sour cream, clementine zest and juice, and vanilla bean paste. Beat until the mixture is smooth, scraping down the sides to ensure even mixing and to remove air pockets.
• Add the eggs and the extra yolk one at a time, mixing briefly after each addition until the filling is homogeneous and creamy.
• Use a spatula to stir the batter a few times to free any remaining air. Pour the filling into the cooled crust and smooth the top; gently tap the pan on the counter to release bubbles.

Baking and Cooling:

• Place a large baking dish on the bottom rack of the oven and set the cheesecake on the middle rack. Carefully pour the boiling water into the baking dish to create a water bath, then close the oven door quickly to retain moisture.
• Bake for about 1 hour and 15 minutes, or until the edges are set and the center still has a slight wobble when gently shaken. Start checking at 1 hour and continue in 15-minute increments if needed.
• Turn off the oven and crack the door open; allow the cheesecake to remain in the oven for 1 hour to cool slowly.
• Remove the cheesecake and cool to room temperature on a rack, then refrigerate for a minimum of 4 hours (overnight is best) to fully set.
• When chilled, carefully remove the springform collar and peel away any parchment. Top with dollops of whipped cream and optional dehydrated orange slices for decoration.
• Use a very sharp knife to slice and serve chilled.

Dehydrated Orange Slices (optional):

• Preheat the oven to 200°F and line a large baking sheet with parchment. Thinly slice one medium orange and arrange the rounds in a single layer on the sheet.
• Bake the orange slices for 2 to 3 hours until they are dehydrated and crisp; they will continue to crisp as they cool. Let cool completely before using as a garnish.