1. In a bowl, place plenty of ice-cold water and submerge 10-12 small dessert or soup plates. Put the cornstarch in another bowl and pour in 2 cups of water. Mix with a whisk until the cornstarch is dissolved. In a non-stick pot, add the remaining water (6 cups) and bring it to a boil. Then, slowly pour in the cornstarch mixture while stirring continuously with a silicone whisk.
2. Reduce the heat to medium and let the Mahalebi simmer for 15-20 minutes. The longer you leave it, the whiter and firmer the Mahalebi will become. Stir occasionally. Don't worry, it won't stick.
3. Drain the plates (without drying them). Spoon 1-2 ladles of the Mahalebi mixture onto each plate and let it cool completely, for 2-3 hours. Place them in the refrigerator to chill.
4. To prevent a skin from forming, pour a little cold water over the top. If you wish, you can remove the Mahalebi from the plates and place them in a large bowl of water. Simply pour a little ice-cold water over the Mahalebi, press around the edges to loosen it from the plate, and then drop it into the bowl of ice-cold water.
5. Serve the Mahalebi, and everyone adds as much rosewater syrup, rosewater sugar, or plain sugar as they desire.
