Preheat your oven to 325°F (163°C).
In a mixing bowl, combine the graham cracker crumbs, melted butter, and sugar. Mix until the crumbs are evenly coated.
Press the crumb mixture firmly into the bottom of the springform pan to form the crust. Bake for 10 minutes and then set aside to cool.
In a large bowl, beat the softened cream cheese with an electric mixer until smooth and creamy.
Gradually add the sugar to the cream cheese, beating until well combined.
Add the eggs one at a time, mixing well after each addition. Then add the vanilla extract, sour cream, and pistachio paste. Mix until smooth.
Pour the cheesecake filling over the cooled crust in the springform pan. Smooth the top with a spatula.
Bake in the preheated oven for about 60 minutes, or until the edges are set and the center is slightly jiggly.
Turn off the oven and leave the cheesecake inside with the door ajar for 1 hour to cool slowly.
Remove the cheesecake from the oven and let it cool to room temperature. Then refrigerate for at least 4 hours or overnight.
For the pistachio cream topping, whip the heavy whipping cream with the powdered sugar until soft peaks form. Gently fold in the pistachio paste.
Once the cheesecake is chilled, spread the pistachio cream over the top and garnish with chopped pistachios.
Slice and serve chilled.