In a bowl, mix the ground graham crackers with the brown sugar and melted butter until it’s well mixed, like gravel.

Line a 7” springform pan with parchment paper on the bottom and around the edge, to prevent sticking.

Pour the crust mixture into the pan and press it down to form a firm crust on the bottom. Pack it down with the bottom of a glass.

In a small mixing bowl, mix cornstarch, salt, and granulated sugar together.

In a medium mixing bowl, beat the cream cheese for a few seconds with a hand mixer on low speed. Add in half the sugar mixture and beat again for a few seconds, just to incorporate the sugar - don’t beat any longer than necessary. Scrape down the bowl with a spatula after each addition.

Add the remaining sugar and beat again just to incorporate.

Add the sour cream, lemon zest and vanilla extract and beat until incorporated.

Beat while adding the eggs, one at a time. Fold the batter with a spatula just to make sure everything is incorporated.

Pour the mixture into the springform pan and smooth it out. Try to remove any air bubbles from the mixture by smoothing with a spatula. You can also tap the pan against the counter a few times to pop bubbles. The smoother the top, the smoother your cheesecake will turn out.

Pour 1 cup of boiling water into the bottom of the Instant Pot. Set the trivet inside. Place the springform pan on the trivet. Lock the lid. Press the pressure cook button and set the time to 27 minutes.

After the time is up, allow a natural release of pressure. Carefully open the lid to avoid water splatter. Remove any water from the surface of the cheesecake with a paper towel.

Allow the cheesecake to cool completely on a wire rack, then transfer it to the refrigerator to cool for at least 4 hours to overnight to firm up.

Once chilled, remove the cake from the pan, top with chocolate syrup, and serve.