In a medium bowl, mix together the chopped spinach, artichoke hearts, cream cheese, mozzarella cheese, Parmesan cheese, minced garlic, olive oil, salt, pepper, and Italian seasoning until well combined. Set aside.
Place the chicken breasts on a cutting board. Using a sharp knife, carefully cut a pocket into each chicken breast without slicing all the way through.
Generously fill each chicken breast with the spinach and artichoke mixture, ensuring they are well-stuffed. Secure the openings with toothpicks if necessary.
Season the outside of the chicken breasts with salt, pepper, and a sprinkle of Italian seasoning.
Heat a large, oven-safe skillet over medium heat. Add a splash of olive oil and sear the stuffed chicken breasts for 3-4 minutes on each side until golden brown.
Transfer the skillet to the preheated oven and bake for 20-25 minutes, or until the chicken is cooked through (internal temperature should reach 165°F or 75°C).
Once cooked, let the chicken rest for 5 minutes before removing toothpicks. Garnish with fresh parsley before slicing.
Notes
Let the chicken rest before serving for better flavor.