Preheat your oven to 325°F (163°C).
In a mixing bowl, combine the graham cracker crumbs, melted butter, and sugar. Mix until well combined.
Press the crumb mixture firmly into the bottom of a 9-inch springform pan to form the crust. Set aside.
In a large bowl, beat the softened cream cheese with an electric mixer until smooth. Gradually add the granulated sugar and continue mixing until creamy.
Mix in the vanilla extract and salt, then add the eggs one at a time, mixing well after each addition.
Fold in the sour cream and chopped pistachios, and if using, the pistachio extract. Mix until just combined.
Pour the cheesecake filling over the prepared crust, spreading it evenly.
Bake in the preheated oven for about 60 minutes or until the center is set but still slightly jiggly.
Turn off the oven, crack the door open, and let the cheesecake cool in the oven for about 1 hour. This helps prevent cracking.
Remove the cheesecake from the oven and let it cool completely at room temperature, then refrigerate for at least 4 hours or overnight.
Before serving, garnish with additional chopped pistachios on top.