2 lg Boneless chicken breasts

           - split
           Salt and pepper; as desired
    1/2 lb Mushrooms

      6 tb Olive oil

    2/3 c  Sherry vinegar

      2 tb Tomato paste

      2 tb Chopped parsley

  TRIM EXCESS SKIN from the breasts. Sprinkle breasts with salt and pepper
  and set aside. Quarter larger mushrooms, halve smaller ones and set aside.
  Heat 1 tablespoon oil in an aluminum skillet or frying pan over high heat
  and brown chicken on skin side. Transfer the chicken to a plate and pour
  off fat. Reduce heat to medium, pour in vinegar and dissolve the tomato
  paste in it. Replace chicken in skillet, skin side up. Cover and cook 3
  minutes. Uncover; cook until chicken is done, 6 minutes. While the chicken
  is cooking, heat 1 teaspoon oil in another frying pan and cook the
  mushrooms about 3-to-4 minutes. Arrange chicken and mushrooms on platter.
  Whisk in the rest of the olive oil; mix in parsley. Pour juices that have
  collected on the platter into sauce. Pour sauce over chicken and mushrooms;
  serve immediately.