Dredge chicken in flour. Heat oil in skillet and brown chicken on both sides, about 7-10 minutes. Stir a little chicken broth into dry mustard and cornstarch to make a paste. Then stir in the rest of the broth; add pepper. When breasts are browned, remove and keep warm; deglaze pan with sherry. Add mustard mixture, return chicken to pan and cook until mixture thickens. Process ricotta with yogurt until smooth. Remove chicken when cooked; turn heat to very low and quickly stir in ricotta mixture. Do not boil. Serve sauce over chicken and sprinkle with parsley. ----