For herb rub, combine the herbs, salt, and pepper. Rinse chicken; pat dry with paper towels. Loosen skin on chicken breast. Using your fingers, carefully spread half of the herb rub under the skin. Skewer neck skin to back; tie legs to tail. Twist wings under back.
In a 1-1/2-quart casserole combine carrots and onions. Toss with the remaining herb rub and the olive oil. Cover; place in oven. Roast about 45 minutes more or until chicken is no longer pink, juices run clear (the meat thermometer, if using, should register 180 degrees F), and vegetables are tender, adding peas to the casserole the last 15 minutes of roasting. If desired, garnish with fresh rosemary. Makes 6 servings.