Preheat the oven to 350°F (180°C) and line a muffin pan with cupcake liners.

In a small bowl, mix the crushed Oreos with melted butter until evenly the texture resembles wet sand. Press about 1½ tablespoons of the mixture firmly into the bottom of each liner. Bake for 5 minutes, then set aside to cool.

In a large mixing bowl, beat the cream cheese and sugar until smooth and creamy.

Beat in the eggs, mixing just until combined.

Add the melted chocolate, cocoa powder, sour cream, and vanilla extract. Mix on low speed until smooth.

Divide the cheesecake batter evenly over the cooled crusts, filling each liner about ¾ full. Bake for 15-18 minutes, until the centers are just set with a slight jiggle.

Remove from the oven and let cool at room temperature for 30 minutes, then refrigerate for at least 2 hours.

In a skillet over medium heat, melt the butter and add the chopped kataifi. Cook, stirring frequently, until golden brown and crisp. Remove from heat and let cool slightly.

Stir in the pistachio cream, chopped pistachios, and melted white chocolate.

Spoon a generous layer of the mixture on top of each chilled cheesecake.

Top each cheesecake with a small dollop of whipped cream. Drizzle with melted chocolate and garnish with pistachios if desired.