Preheat your oven to 350°F (175°C). In a food processor, combine cookie crumbs, melted butter, salt, and powdered sugar. Pulse until the mixture resembles wet sand. Press the mixture into the bottom of an 8-inch cake pan. Bake for 10 minutes until lightly golden, then chill.

Lower the oven temperature to 325°F (160°C). In the food processor, blend cream cheese, granulated sugar, and a pinch of salt until ultra-smooth. Add vanilla extract, pistachio butter, and sour cream. Blend again until creamy.

With the motor running, add eggs one at a time, pulsing gently after each addition. Mix in lemon zest if desired, maintaining a smooth filling.

Pour the filling into the chilled crust, spreading evenly. Place the cake pan in a larger dish filled with hot water, creating a water bath. Bake for approximately 50 minutes until edges are set and center jiggles slightly.

Once baked, turn off the oven and crack the door. Allow to cool in the oven for 30 minutes, then transfer to room temperature. Refrigerate for at least 8 hours, preferably overnight.