Place the rice in a large pot and rinse under cold running water until the water runs clear. Drain well and add 4 1/2 cups water to the pot. Sprinkle with the salt and add the butter, ginger and lemon zest. Bring to a boil, then reduce heat to a simmer. Cover and cook 15 minutes without removing the lid.
Remove the lid and fluff the rice with a fork. Cover again and keep warm until ready to serve. For drier rice, leave the lid off after fluffing. Sprinkle with the chopped cilantro before serving.