In a shallow bowl, combine flour and pepper; dredge the chicken. Set remaining flour mixture aside. In a skillet, brown chicken in oil; transfer to an ungreased 9-in. square baking dish. , In a saucepan, saute onion in butter. Add reserved flour mixture; stir to form a thick paste. Gradually add broth, lemon juice, basil and thyme; mix well. Bring to boil; cook and stir for 2 minutes or until thickened and bubbly. Pour over the chicken. Top each half with a lemon slice. Sprinkle parsley. Cover and bake at 350° for 25-30 minutes or until the juices run clear. Serve over rice if desired.