Preheat the oven to 325°F (160°C).
In a mixing bowl, combine graham cracker crumbs and melted butter. Press the mixture firmly into the bottom of the 9-inch springform pan to form the crust. Set aside.
In a large mixing bowl, beat the softened cream cheese and granulated sugar using an electric mixer until smooth and creamy.
Add in the eggs one at a time, mixing well after each addition. Scrape down the sides of the bowl as needed.
Incorporate the vanilla extract, orange zest, and fresh orange juice into the cream cheese mixture. Mix until well combined.
Add sour cream and cornstarch to the mixture. Beat until smooth.
Pour the cheesecake batter over the prepared crust in the springform pan.
Place the springform pan inside a larger baking pan. Fill the larger pan with hot water halfway up the sides of the springform pan (this acts as a water bath).
Bake in the preheated oven for 60 minutes, or until the center is set but slightly jiggly.
Turn off the oven and leave the cheesecake inside for an additional hour to cool gradually.
Remove the cheesecake from the oven and the water bath, and let it cool to room temperature.
Cover with plastic wrap and refrigerate for at least 4 hours, preferably overnight, before serving.