01 - Preheat oven to 340°F. Line the bottom of a 9-inch springform pan with parchment paper and grease the sides.
02 - Mix crushed graham crackers, melted butter, chopped pistachios, and sugar in a bowl. Press the mixture into the base of the prepared pan. Bake for 10 minutes. Cool completely.
03 - In a large bowl, beat cream cheese and sugar until smooth and fluffy. Add yogurt or sour cream and vanilla extract, mixing until well combined.
04 - Add eggs one at a time, mixing gently after each addition to maintain airiness.
05 - Stir in ground pistachios and cornstarch until fully incorporated and no lumps remain.
06 - Pour the filling over the cooled crust. Tap the pan gently to release air bubbles. Bake in the preheated oven for 45 minutes or until the edges are set and the center still slightly jiggles.
07 - Turn off the oven, open the door slightly, and let the cheesecake cool inside for 1 hour to prevent cracking.
08 - Cool to room temperature, then refrigerate for at least 4 hours, preferably overnight, for optimal texture.
09 - Whip the cream with powdered sugar to soft peaks. Spread over the chilled cheesecake and sprinkle with chopped pistachios just before serving.