Chop the chicken in half then season both halves with enough salt and pepper. Heat the olive oil in the hot frying pan and sear the chicken breasts for at least 3 minutes. Turn the chicken over and cook for 3 more minutes.
While frying the chicken, make the mushroom sauce in another pan. Sauté the mushrooms in oil with the onion and garlic. Stir for 3 minutes then throw in the cilantro. Pour the heavy cream into the pan with pepper and salt to season. Simmer for 5 minutes.
Transfer the chicken to a plate. Spread the mushroom sauce on top.