Begin by preparing the syrup: Combine the sugar, water, and rose water in a saucepan. Bring it to a boil to dissolve the sugar, then reduce the heat and let it simmer for 5 minutes before allowing it to cool. Cut 1 cup of the pistachios in half and finely grind the remainder. Melt the butter in a separate container. Unpack the kadaifi dough and keep it covered with a towel to prevent it from drying out. Take 15g of kadaifi, brush it with melted butter, and carefully roll it into a nest shape using your fingers, ensuring the edge is secured underneath. Arrange the nests in a round baking pan. Place a spoonful of the halved pistachios in the center of each nest. Drizzle the remaining butter over the nests. Bake in a preheated oven at 180°C (fan setting) for 30 minutes or until they are golden brown. Once out of the oven, immediately pour the cold syrup over the hot nests. Let them rest for 1-2 hours to fully absorb the syrup. Top each nest with a spoonful of the ground pistachios before serving.