In a medium sized pot with lid, bring the stock, saffron, and salt to a boil. Once mixture is boiling, add the basmati rice. Reduce the heat to a low simmer, cover and cook for 20 minutes. After the 20 minutes, remove the rice from the heat and let cool for a few minutes while you gather the other ingredients. In the rice pot or a bowl, fluff the rice with a fork and gently toss in everything except the scallions, mixing until well incorporated. Garnish with sliced scallions and serve.