Prep the oven: Heat your oven to 375°F (190°C).
Line a sheet pan with parchment or lightly oil a baking dish.
Season the chicken: Pat the chicken breasts dry. In a small bowl, mix salt, pepper, garlic powder, and smoked paprika. Sprinkle evenly on both sides.
Make the filling: In a bowl, combine cream cheese, spinach, mozzarella, Parmesan, minced garlic, parsley (or Italian seasoning), and lemon zest.
Stir until smooth. If using extras like sun-dried tomatoes, fold them in now.
Cut pockets: Place your hand flat on each chicken breast. With a sharp knife, slice horizontally to create a deep pocket, stopping about 1/2 inch from the other side.
Don’t cut all the way through.
Stuff carefully: Spoon the filling evenly into the pockets. Press the chicken closed and secure with 2–3 toothpicks along the seam so the filling stays put.
Sear for crust: Heat 1 tablespoon olive oil in an oven-safe skillet over medium-high heat. When hot, add the chicken.
Sear 2–3 minutes per side until lightly golden. Don’t cook through here—just build color.
Finish in the oven: Transfer the skillet to the oven (or move the chicken to your prepared baking dish). Bake 12–18 minutes, depending on thickness, until the thickest part reaches 165°F (74°C).
Rest and serve: Let the chicken rest 5 minutes.
Remove toothpicks. Squeeze a little lemon over the top and serve with a simple salad, roasted veggies, or rice.