Preheat your oven to 325°F (160°C).

In a medium bowl, combine the graham cracker crumbs, granulated sugar, and melted butter. Press this mixture into the bottom of a 9-inch springform pan and bake for 8-10 minutes. Let it cool.

Using a stand mixer, beat the softened cream cheese until smooth. Add sugar and vanilla extract, mixing until combined.

In a separate bowl, whip the heavy cream until stiff peaks form and gently fold it into the cream cheese mixture.

Stir in the chopped pistachios and, if desired, the pistachio pudding mix.

Pour the cheesecake filling over the cooled crust, smooth it out, cover with plastic wrap, and chill in the refrigerator for at least 4 hours (overnight is recommended).

Remove the cheesecake from the springform pan, garnish with extra pistachios and whipped cream if desired, slice, and serve.