Add olive oil, garlic, Italian seasoning, salt, pepper, and red pepper flakes into a Ziploc bag. Seal the bag and shake until mixed. Add the chicken breasts, seal, and massage so the chicken is covered in the marinade, set aside for a minimum of an hour.
Position a rack in the center of the oven and preheat the oven to 400ºF
Heat a medium sized skillet with olive oil over medium heat. Add in mushrooms. Cook mushrooms down to start to cook off some liquid. Add in the spinach to quickly wilt, set aside.
Stir together the parsley with the softened cream cheese, set aside.
Arrange chicken breasts in a baking dish coated with cooking spray. Spread the softened cream cheese mixture over the chicken and sprinkle Monterey cheese on top of the cream cheese. Then, lay the spinach mixture over the cheese. Finally, lay provolone slices on top.
Bake the chicken casserole for 25-30 minutes. Chicken is done when cooked through to an internal temperature of 165˚F (75°C). Serve warm with a side of cauliflower rice, or baked veggies. Enjoy!
Notes
Two ways you can switch up this recipe:
Omit the mushrooms all together if you aren't a fan
Swap out the provolone for some chopped marinated fresh mozzarella