Combine graham cracker crumbs with butter. Press into the bottom and partially up the sides of a 9 inch spring form pan. Refrigerate.
Preheat the oven to 300 °F. Fill a shallow pan half full of hot water and place on the lower rack to minimize cracking.
Beat cream cheese, sugar, lime zest, and cornstarch in a large bowl with an electric mixer until smooth and fluffy. Beat in eggs one at a time, blending just until smooth. Add Key lime juice with the mixer on low. Finish mixing by hand. Mix until just combined. Pour batter into the prepared crust.
Bake in the preheated oven for 55 to 65 minutes, or until set.
Turn the oven off, and let the cheesecake stand in the oven for 30 minutes with the door open at least 4 inches. Remove the cheesecake from the oven.
Refrigerate cheesecake for at least 8 hours.
Notes
You can juice regular limes or buy key lime juice. Squeezing small fresh key limes is tedious and doesn't make that big of a difference.
This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.