Preheat oven to 180°C.
Bring the water, rose water, lemon juice and sugar to a boil for 15 minutes then set aside.
Separate the kadaïfs with your fingers then add the clarified butter and mix well.
Press a bit more than half the mixture down into a rectangular casserole dish, pushing the mixture up the sides.
Sprinkle on the shredded 40% fat Maestrella Mozzarella then the remaining kadaïf.
Pat down the mixture and bake for 20 minutes until the kunafa is golden brown.
Drizzle on the cooled syrup and garnish with pistachios.