Preheat the oven to 350 degrees, if not still preheated.
Put a pot of water on the stove to start boiling. You will want enough water to go up about 1 ½ inches on the sides of the springform pan.
In a stand mixer, mix the cream cheese, corn starch and sugar together with a paddle attachment on medium speed for 1-2 minutes until everything is smooth and there are no lumps. (You can alternatively use a hand mixer, but just be careful not to overmix). Half way through, scrape down the sides and bottom of the bowl to ensure everything has been mixed well.
32 oz (907 g) cream cheese, softened, 1 ¼ cups (250 g) granulated white sugar, ¼ cup (32 g) cornstarch
Add in the pumpkin puree, sour cream, pumpkin pie spice and vanilla and mix on medium low speed just until combined. (Scrape sides and bottom of bowl again).
1 cup (244 g) canned pumpkin puree, ⅓ cup (82 g) sour cream, at room temperature, 1 tablespoon pumpkin pie spice, 1 tablespoon vanilla extract
Next add in the eggs and egg yolks and mix on medium low speed just until combined. Do not over mix the batter.
3 whole eggs, at room temperature, 2 egg yolks, at room temperature
Pour the batter into the prepared pan with the crust.
Place the cheesecake in a large roasting pan in the oven. Slowly pour the boiling water into the roasting pan around the cheesecake being careful not to splash the cheesecake.
Bake for 1 hour. When an hour is up, turn off the oven and crack the door open. It helps to use a wooden utensil to keep the oven door slightly open. Let the cheesecake stay in the oven for an additional 1 hour. The cheesecake will continue to bake as it is cooling.
Once the 2 hours are up, remove the cheesecake from the oven and go around the edges of the pan with a butter knife to loosen the crust from the sides of the pan.
Let the cheesecake cool completely on the counter, then cover the pan with plastic wrap and refrigerate for at least 8 hours, or overnight.