Cook the noodles: Boil the rice noodles in salted water until tender but not mushy. Drain and rinse under cold water. Spread them on a tray and freeze for about 1 hour.
Make the syrup: In a saucepan, combine sugar and water. Heat until the sugar dissolves. Remove from heat and stir in rosewater and lime juice. Let it cool slightly.
Combine noodles and syrup: Gently mix the chilled noodles with the syrup. Spread evenly in a shallow dish and freeze for 2–3 hours until slushy but not solid.
Serve: Scoop into bowls, and garnish with pistachios, rose petals, and sour cherry jam. Optional: serve with a scoop of Persian saffron ice cream.