Make the marinade in a small bowl by whisking together the honey, Dijon mustard, mayonnaise, and lemon juice. Reserve 1/3 cup for dipping and place the rest of the marinade into a large resealable bag with the chicken breasts. Marinate the chicken for 3 hours or overnight.
Preheat your oven to 400 degrees F and grease a casserole dish with nonstick cooking spray. Set aside.
Add 2 tablespoons of butter to a large skillet over medium heat. Once the butter is sizzling, pour in the chicken and marinade from the bag. Cook for about 4 minutes per side or until the chicken has a nice sear. (Do not cook the chicken all the way through, it will finish cooking in the oven.) Transfer the chicken to the prepared casserole dish.
Wipe out the skillet and return it to the stove. Add 1 tablespoon of butter to the skillet and cook the mushrooms for about 6 minutes. They should still be stiff but starting to become tender and brown.
Evenly divide the mushrooms over the chicken. Top each chicken breast with 2 slices of cooked bacon and 1/4 of the shredded cheese.
Bake for 10-15 minutes until the chicken reaches 165 degrees F internal temperature and the cheese is melted.
Use the remaining marinade as a dip or it drizzle over the chicken. Garnish with freshly chopped parsley before serving warm.