Pat the chicken dry with paper towels. Use a sharp knife to cut each chicken breast in half horizontally to create two chicken breast halves.
Place each breast flat between 2 sheets of plastic wrap and pound until it reaches an even thickness of about 1/4 inch. (Be careful not to tear the chicken).
On a wide flat plate, add flour, salt, and pepper. Dredge the chicken in the flour mixture, coating all sides.
Heat 1 tablespoon of the olive oil and 1 tablespoon of the butter in the skillet over medium heat until sizzling (reserving the rest).
Working in batches, add 4 of the chicken halves (do not try to overcrowd the pan) and saute about 6 minutes on each side, or until the internal temperature of the chicken is 165°F.
Transfer to a plate and set aside (tent to keep warm).
Heat the remaining oil and butter until sizzling.
Saute the remaining chicken halves, making sure the internal temperature reaches 165°F.
Transfer to the same plate.
In a medium bowl combine cornstarch and chicken stock. Whisk until combined. Add the marsala wine and mix well.
Pour the marsala mixture into the pan. Use a wooden spoon to scrape up any brown bits in the pan.
Add the mushrooms and cook over medium heat (turning occasionally) until the sauce has thickened (about 5 minutes).
Nestle the cooked chicken in the marsala sauce and top with fresh parsley. Serve over noodles.