In a pan over medium heat, add the oil and butter. Once the butter melts, add the chicken breasts cut into pieces, season with salt and pepper, and sear the meat (do not brown it). Set the meat aside and in the same pan, add the chopped onion, season with salt, and sauté. Once the onion is ready, add the flour and cook a little, then add the beef broth.

Stir and add the whiskey, cook for a few minutes, then add the ketchup, mustard, and Worcestershire sauce, and continue cooking. In another pan with a little oil, sauté the mushrooms cut into pieces or slices. Once the mushrooms are sautéed, add them to the pan with the sauce along with the reserved chicken, including all the juices released.

Season with a little more salt and pepper, cover, and let it cook on low heat for 10 minutes. After 10 minutes, add the cream and cook for another 4 or 5 minutes. Just before finishing, adjust the salt if necessary and it's ready to eat. Serve immediately. Try it, you'll love it.