Sauté mushrooms in olive oil. Set aside. Sauté chicken in same pan when browned on both sides add mushrooms back in pan and add Marsala wine, chicken bullion, and water. Simmer for 15 minutes. Mix cornstarch to 1/4 cup water and thicken chicken mixture
Take the time to Filet the chicken, it will speed up the cooking process. Also when you are browning the chicken it doesn't need to be cooked all the way through. You will be sauteing the chicken with the mushrooms, wine and chicken broth for a good 30 minutes so the chicken will finish cooking during this time.
And like I always say "Enjoy the Journey"