Fry onions and peppers and leave aside.
Dissolve the saffron in milk. Add this to cooked rice and mix. In a casserole dish, sprinkle a few fried onions, spread 1/2 the rice over the onions and spread the vegetable over the rice. Place half of the green pepper rings and put the remaining rice, then cover with remaining onions and pepper rings. Cover and bake at 400 degrees for 15-20 minutes. Serve hot.