In medium bowl, place chicken and buttermilk; cover and marinate in refrigerator 15 minutes. In small bowl, whisk together olive oil, vinegar and mustard; place in large frypan and add chicken in single layer. Saute over medium heat 6 minutes per side. Transfer chicken, meatiest side up, to 13x9x2-inch baking dish lined with foil. In medium bowl, mix together baking potato, yam, brown sugar, bread crumbs and parsley flakes; spoon evenly over chicken. Bake in 350 degree F. oven about 45 minutes or until chicken is fork tender. Garnish with red leaf lettuce.