Steps
Preheat your oven to 375°F (190°C).
In a small bowl, mix together the chopped spinach, cream cheese, mozzarella, Parmesan, garlic powder, salt, and pepper until well combined.
Take the chicken breast and carefully slice it horizontally to create a pocket.
Stuff the spinach and cheese mixture into the chicken breast pocket.
Heat the olive oil in a skillet over medium heat and sear the chicken breast for about 3-4 minutes on each side until golden brown.
Transfer the chicken to a baking dish and bake in the preheated oven for 20-25 minutes or until the chicken is cooked through and the juices run clear.
Let it rest for a few minutes before slicing and serving.