Bring 3 cups of water to the boil. Add rock sugar. Cook over low heat until the sugar has dissolved. Strain. Pour syrup into a steaming pot.
Wash pumpkin. Cut into dices. Rince dried longan. Put pumpkin dices and dried longan into steaming pot. Stew for 40 minutes. Add bird’s nest. Then stew for 10 minutes. Serve.