Prepare the syrup: In a saucepan over medium heat, combine sugar, water, and lemon juice. Stir until the sugar dissolves, then simmer for 5 minutes. Remove from heat and add orange blossom water. Let cool.

Prepare the kataifi base: Preheat oven to 350°F (175°C). In a bowl, mix the shredded kataifi pastry with melted butter until fully coated.

Assemble the base: Press half of the kataifi mixture into a greased baking dish, forming an even layer.

Prepare the filling: In a bowl, mix mozzarella, ricotta, vanilla extract, and sugar until smooth. Spread the cheese mixture over the kataifi layer.

Melt the chocolate: Heat heavy cream until warm (not boiling), then pour over chopped chocolate. Stir until smooth. Pour over the cheese layer.

Top with kataifi: Cover the filling with the remaining kataifi mixture, pressing gently.

Bake: Place in the oven and bake for 30-35 minutes, or until golden brown.

Finish with syrup: Remove from oven and immediately drizzle the cooled syrup over the hot knafeh. Let it soak for 10 minutes.

Garnish and serve: Sprinkle with crushed pistachios, slice into bars, and enjoy warm!