Hot cooked rice (optional) *Note: Chicken should be skinned, boned and cut into thin strips. Season chicken with pepper to taste. In large skillet, stir-fry chicken in oil until lightly browned and tender. Remove chicken from pan and set aside. Add butter to pan and stir-fry garlic and onion until onion is just tender. Add zucchini, mushrooms and carrot and stir-fry over medium heat 3 minutes. Add chicken and heat through. Stir in lemon peel and juice and walnut halves. Toss to mix. Serve over hot rice, if desired.