Pour off all but 2 tablespoons fat from skillet. Cook onion and garlic with 1/4 teaspoon each of salt and pepper over medium heat, stirring, until golden, about 6 minutes. Add rice and cook, stirring, 1 minute. Add broth, water, saffron, and bay leaf and bring to a full boil. Nestle chicken in rice, keeping as much rice around (rather than under) chicken as possible, and add juices from plate. Simmer, covered tightly with lid, over low heat until chicken is cooked through, rice is tender, and most of liquid is absorbed, about 25 minutes. Remove from heat and stir in peas. Cover with a kitchen towel and then lid and let stand until all of liquid is absorbed, about 15 minutes. Discard bay leaf.
