Steps
1. Preheat your oven to 190°C (375°F).
2. In a skillet, heat olive oil over medium heat. Add the minced garlic and diced mushrooms, sautéing until the mushrooms are soft.
3. Add chopped spinach to the skillet and cook until wilted. Remove from heat and let cool slightly.
4. In a bowl, mix the cream cheese, shredded mozzarella, sautéed mushrooms, and spinach. Season with salt, pepper, and Italian seasoning if using.
5. Carefully cut a pocket in the chicken breast and fill it with the cheese mixture.
6. Secure the opening with toothpicks if necessary. Season the outside of the chicken with salt and pepper.
7. Place the stuffed chicken breast in a baking dish and bake for 25-30 minutes, or until the chicken is cooked through and the juices run clear.
8. Let it rest for a few minutes before slicing and serve warm.