Lightly grease a 7-inch springform pan with butter or nonstick spray. If the pan has a loose base, line the bottom with a round of parchment paper for easier release.

In a medium bowl, stir together the graham cracker crumbs, 2 tablespoons sugar, melted butter, and 1/8 teaspoon fine sea salt until the mixture looks like damp sand and holds together when pressed. If it seems too dry, add another teaspoon of melted butter.

Pour the crust mixture into the prepared pan. Use your fingers or the bottom of a flat measuring cup to press it firmly and evenly across the bottom and about 1 inch up the sides. Pack it tightly so it doesn’t crumble when sliced. Place the pan in the freezer while you prepare the filling.

In a large bowl, beat the softened cream cheese with a hand mixer on medium speed until completely smooth, 1–2 minutes. Add 2/3 cup granulated sugar and beat again until the mixture is fluffy and no graininess remains, scraping down the bowl as needed.

Add the sour cream, heavy cream, vanilla extract, cornstarch, and 1/8 teaspoon fine sea salt to the bowl. Mix on low speed just until combined and creamy, avoiding overmixing to prevent excess air in the batter.

Add the eggs one at a time, beating on low speed just until each egg is incorporated. Stop the mixer as soon as the batter looks smooth. Use a spatula to gently stir the batter and make sure there are no streaks at the bottom of the bowl.

Remove the crust from the freezer and pour the cheesecake filling over it. Tap the pan firmly a few times on the counter to release air bubbles. If you see large bubbles on top, pop them with a toothpick and smooth the surface.

Tightly cover the top of the springform pan with a piece of aluminum foil to prevent condensation from dripping onto the cheesecake and to help create a smooth top.

Pour 1 cup of water into the bottom of a 6-quart (or larger) Instant Pot. Place the trivet in the pot. If your trivet has no handles, make a foil sling. Set the covered springform pan on the trivet.

Lock the lid and set the valve to Sealing. Cook on High Pressure for 35 minutes. This timing is for a 7-inch pan; very thick or different-sized pans may need slight adjustment.

When the cook time ends, let the pressure release naturally for 10 minutes. Then carefully turn the valve to Venting to release any remaining pressure. Lift the cheesecake out using the trivet handles or foil sling.

Remove the foil cover. Gently nudge the pan; the center of the cheesecake should jiggle slightly like Jell-O but should not look liquid, and the edges should be set. If it seems too loose or wet, re-cover with foil, return to the Instant Pot, and cook for an additional 3–5 minutes at High Pressure followed by another 10-minute natural release.

Run a thin knife around the edge of the cheesecake between the cake and the pan to loosen it and help prevent cracking as it cools. Let the cheesecake cool at room temperature in the pan for about 1 hour.

Cover the pan (you can reuse the foil) and refrigerate the cheesecake for at least 4 hours, preferably overnight, until fully chilled and set with a dense, creamy texture.

When ready to serve, release and remove the springform ring. Slice with a sharp knife, wiping the blade between cuts for clean slices. Serve plain or topped with fresh berries, fruit sauce, chocolate drizzle, or caramel.