Heat butter in medium heavy saucepan and fry cumin seeds, cinnamon stick, cardamom, cloves, peppercorns and bay leaves for about 2 minutes. Add rice and fry for 2 - 3 minutes more. Stir in salt, chicken stock and saffron. Cover and bring to a boil. Reduce heat to low and cook for 10 minutes. Remove from heat. After 5 minutes, fluff with fork.