Prepare the Crust:

• Combine graham cracker crumbs with melted butter.
• Press the mixture into the bottom and slightly up the sides of a 9-inch springform pan.
• Refrigerate while preparing the filling.

Preheat the Oven:

• Set oven to 300°F (150°C).
• Place a shallow pan filled halfway with hot water on the lower oven rack to create moisture, which helps prevent cracking.

Make the Filling:

• In a large bowl, beat cream cheese, sugar, lime zest, and cornstarch until smooth and fluffy.
• Add eggs one at a time, mixing just until smooth after each addition.
• On low speed, mix in key lime juice until fully incorporated (avoid overmixing).

Assemble & Bake:

• Pour the filling into the prepared crust.
• Place the cheesecake on the middle rack above the water-filled pan.
• Bake for 55 to 65 minutes, or until the center is set but slightly jiggly.

Cool Gradually:

• Turn off the oven and prop the door open about 4 inches.
• Let the cheesecake sit inside for 30 minutes to cool slowly.

Chill & Serve:

• Refrigerate the cheesecake for at least 8 hours (or up to 3 days) before serving.
• Garnish with whipped cream and lime zest if desired.