Heat the oil in a heavy pot. Add the scallions and sauté over medium heat, stirring, until wilted, 5 minutes. Add the saffron and cook for 2 minutes longer.
Add the rice and stir, coating the grains well with oil. Season with the 1½ teaspoons salt, pour in the chicken stock, and stir. Bring to a simmer, cover, and cook over low heat until the rice is just done