Gather your ingredients. Leah Maroney
Cover the chicken breasts with the honey mustard in a large bowl. Cover with plastic wrap and allow to marinate in the refrigerator for at least 2 hours, and up to over night. Leah Maroney
Preheat the oven to 400 F. Heat the butter in a sauté pan over medium heat. Add the mushrooms and a pinch of salt, and allow to brown and soften for a few minutes. Stir every minute or so to make sure the mushrooms brown evenly. Leah Maroney
Remove the mushrooms from the sauté pan and set them aside. Add a tablespoon of olive oil to the pan and bring back up to medium heat. Add the chicken to the pan, making sure to allow the excess marinade to drip off first. Cook for five minutes per side. Do not try to move or turn the chicken before the five minutes is up, to allow for thorough browning. Flip the chicken and brown on the other side. Leah Maroney
Remove the pan from the heat. The chicken will continue cooking in the oven, so don't worry about the internal temperature yet. Place the mushrooms and chopped bacon over the top of the chicken, then top each with shredded cheese. Cover the pan with an oven-safe lid, transfer to the preheated oven and bake for 15 minutes. Leah Maroney
Remove the chicken from the oven and test it with a meat thermometer to make sure it has reached an internal temperature of 165 F. Garnish with chopped parsley and serve immediately.