01 - Preheat oven to 350°F. Line a baking sheet with parchment paper.
02 - Gently separate kataifi strands in a mixing bowl. Drizzle with melted butter and powdered sugar. Toss until all pieces are evenly coated.
03 - Evenly spread the kataifi mixture on the prepared baking sheet. Bake for 15 to 18 minutes, stirring once halfway, until golden and crisp. Set aside to cool completely.
04 - In a food processor, blend pistachios and powdered sugar until finely ground. Add heavy cream, orange blossom water (if using), and salt. Process until the mixture forms a thick, spreadable paste.
05 - Line an 8x8 inch square pan with parchment paper. Press half of the cooled kataifi into the bottom to form an even, compact layer.
06 - With a spatula, evenly spread the pistachio mixture over the kataifi base.
07 - Top with remaining kataifi, pressing down gently. Transfer pan to freezer for 20 minutes, allowing layers to set firmly.
08 - Melt chocolate and neutral oil together in a heatproof bowl set over a saucepan of simmering water, stirring until smooth. Cool slightly before coating.
09 - Remove pan from freezer. Lift layered block from the pan using parchment overhang. Slice into 12 uniform bars using a sharp knife.
10 - Dip each bar into melted chocolate, turning to coat all sides. Place bars on a parchment-lined tray. Sprinkle with chopped pistachios and rose petals before the chocolate hardens.
11 - Refrigerate bars until the chocolate is completely firm. Store in an airtight container in the refrigerator until serving.