Prep the oven and pan. Heat oven to 350°F (175°C).
If using a water bath, bring a kettle of water to a boil. Wrap the outside of your pie pan with a wide sheet of heavy-duty foil to prevent leaks.
Make the crust. In a bowl, combine graham cracker crumbs, sugar, salt, and melted butter. Stir until the mixture looks like damp sand and holds together when pressed.
Press and pre-bake. Firmly press the crumbs into the bottom and up the sides of the pie pan.
Bake for 8–10 minutes until fragrant and lightly set. Cool for 5 minutes while you make the filling. Reduce oven to 325°F (160°C).
Soften and smooth the cream cheese. Beat cream cheese on medium speed for 1–2 minutes until completely smooth, scraping the bowl. No lumps should remain before adding other ingredients.
Add sugar and salt. Mix in granulated sugar and salt until glossy and blended, about 1 minute.
Avoid whipping too much air into the batter.
Blend in sour cream, heavy cream, and vanilla. Add them along with cornstarch if using. Mix on low just until combined. The batter should be silky and thick.
Add eggs last. Beat in eggs one at a time on low, mixing only until each is incorporated. Do not overmix; too much air causes cracks.
Fill the crust. Pour the batter into the warm crust.
Gently tap the pan on the counter to pop any big bubbles. Smooth the top with a spatula.
Set up the water bath (optional but helpful). Place the foil-wrapped pie pan in a roasting pan. Pour hot water into the roasting pan to reach halfway up the pie pan sides.
This creates gentle, even heat.
Bake. Bake at 325°F (160°C) for 40–50 minutes. The edges should be set while the center still wobbles slightly like Jell-O. If it looks liquid, give it 5 more minutes and check again.
Cool gradually. Turn off the oven, crack the door, and let the cheesecake sit inside for 30 minutes.
Then remove from the oven and water bath. Cool on a rack until barely warm.
Chill to set. Cover loosely and refrigerate for at least 6 hours, preferably overnight. The texture firms up and flavors develop fully.
Slice and serve. Warm a sharp knife under hot water, dry it, and slice.
Wipe the blade between cuts for clean edges. Add toppings if you like.