Heat the oven to 350°F/175°C.

Line a 9-inch/23 cm round cake pan with parchment paper. Layer 6 sheets of phyllo in the pan, brushing each one with melted butter. Allow the edges to hang slightly over the sides. Bake for 10 minutes, just until lightly golden. Do not brown—this is a partial bake.

In a medium bowl, combine the pistachios, rose water, and 2 tablespoons of the sugar. Mix and set aside.

In a large bowl, whisk the cream cheese, heavy cream, eggs, flour, remaining sugar, and vanilla extract until completely smooth and lump-free.

Spread the pistachio mixture evenly over the warm phyllo crust. Pour the cheesecake filling on top. Tear 1 to 2 sheets of phyllo into strips, scrunch them, and scatter over the surface of the batter. Brush generously with more melted butter.

Return the cake to the oven and bake for 1 hour, until puffed and golden. If the top browns too quickly, tent loosely with foil during the last 15 minutes.

Meanwhile, in a small microwave-safe bowl, combine the syrup ingredients. Microwave for 40 seconds, or until the sugar is fully dissolved. Stir and let cool slightly.

As soon as the cheesecake comes out of the oven, spoon the warm syrup over the surface. Let cool completely, then refrigerate at least 6 hours or overnight, until firm.

Just before serving, garnish with more chopped pistachios and edible rose petals, if using.