Preheat oven to 375°F (190°C).
Slice the chicken breasts horizontally to create a pocket without cutting all the way through.
Stuff each chicken breast with mozzarella, roasted red peppers, and spinach.
Secure the openings with toothpicks or kitchen twine.
Brush each chicken breast with olive oil.
Season both sides with salt, pepper, garlic powder, and paprika.
Heat an oven-safe skillet over medium heat and sear the chicken for 3–4 minutes on each side until golden.
Transfer skillet to oven and bake for 15–20 minutes, or until chicken reaches 165°F internally.
Let rest for 5 minutes before serving. Remove toothpicks or twine before serving.