Preheat oven to 375°F (190°C) and grease a 9x13 inch baking dish.
Season chicken breast cutlets with salt and pepper on both sides.
In a large skillet over medium-high heat, heat olive oil and sear chicken for 2-3 minutes per side until golden but not fully cooked through. Transfer chicken to the prepared baking dish.
In the same skillet, add sliced mushrooms and sauté for 5 minutes until browned and moisture has evaporated.
Add minced garlic and fresh spinach to the skillet, tossing for 1-2 minutes until spinach is wilted. Remove from heat.
Spread a layer of softened cream cheese over the top of each chicken breast in the baking dish.
Layer the mushroom and spinach mixture evenly over the cream cheese layer.
Top the assembly with shredded mozzarella and grated parmesan cheese.
Bake for 15-20 minutes until the chicken reaches an internal temperature of 165°F (74°C) and the cheese is bubbly.
Allow the dish to rest for 5 minutes before serving to let juices redistribute.