Prep the oven and pan: Preheat your oven to 400°F (200°C).
Lightly grease a baking dish or line a sheet pan with parchment.
Mix the filling: In a bowl, combine cream cheese, mozzarella, Parmesan, garlic, parsley, chives, onion powder, Italian seasoning, paprika, red pepper flakes, lemon zest, and a pinch of salt and pepper. Stir until smooth.
Butterfly the chicken: Place a chicken breast on a cutting board. With your hand flat on top, slice horizontally to create a pocket, stopping about 1/2 inch from the edge.
Don’t cut all the way through. Repeat with the remaining breasts.
Season the chicken: Pat dry. Rub the outside with olive oil or melted butter.
Sprinkle both sides with salt, pepper, and a little extra Italian seasoning or paprika if you like.
Stuff generously: Spoon the cream cheese mixture evenly into each pocket. Don’t overfill to the point of bursting. Use toothpicks to secure the open edges.
Quick sear (optional but recommended): Heat a skillet over medium-high with a drizzle of oil.
Sear chicken 1–2 minutes per side until lightly golden. Transfer to the baking dish. This step adds color and helps lock in juices.
Bake: Place the chicken in the oven and bake 18–25 minutes, depending on thickness, until the internal temperature reaches 165°F (74°C).
The cheese will be melty and the juices should run clear.
Rest and serve: Let the chicken rest 5 minutes before slicing to keep it juicy. Remove toothpicks before serving.