Preheat the oven to 325°F (163°C). Wrap the outside of a 9-inch springform pan with two layers of heavy-duty aluminum foil to prevent water leakage.

In a medium bowl, combine graham cracker crumbs, ground pistachios, and melted butter. Press the mixture firmly into the bottom of the prepared springform pan.

Bake the crust for 10 minutes. Remove from the oven and set aside to cool completely.

In a large mixing bowl, beat the softened cream cheese and granulated sugar on medium speed until smooth and creamy, approximately 3 minutes.

Incorporate the sour cream, pistachio paste, and vanilla extract, mixing until fully combined.

Add the eggs one at a time, mixing on low speed after each addition just until the yellow disappears to avoid incorporating excess air.

Pour the cheesecake batter over the cooled crust. Place the springform pan inside a large roasting pan and fill the roasting pan with hot water until it reaches halfway up the sides of the springform pan.

Bake for 70 to 75 minutes, or until the edges are set and the center has a slight jiggle.

Turn off the oven and crack the door slightly. Let the cheesecake cool in the water bath inside the oven for 60 minutes.

Remove the pan from the water bath, remove the foil, and refrigerate for at least 8 hours or overnight.

To make the topping, heat the heavy cream until simmering, then pour over the chopped white chocolate. Let sit for 5 minutes, stir until smooth, and spread over the chilled cheesecake.

Garnish the edges with crushed pistachios before slicing and serving.