In a large skillet, brown chicken in butter. Remove chicken to an ungreased 13x9-in. baking dish. Arrange artichokes and mushrooms on top of chicken; set aside. , Saute onion in pan juices until crisp-tender. Combine the flour, rosemary, salt and pepper. Stir into pan until blended. Add chicken broth. Bring to a boil; cook and stir until thickened and bubbly, about 2 minutes. Spoon over chicken. , Bake, uncovered, at 350° until a thermometer inserted in the chicken reads 165°, about 40 minutes. Serve with noodles and sprinkle with parsley. Freeze option: Cool unbaked casserole; cover and freeze. To use, partially thaw in refrigerator overnight. Remove from refrigerator 30 minutes before baking. Preheat oven to 350°. Bake casserole as directed, increasing time as necessary to heat through and for a thermometer inserted in the chicken to read 165°.