Step 1: Prepare the chicken breasts. Place each chicken breast between two sheets of plastic wrap and pound evenly to about 1/2 to 3/4 inch thickness. Season both sides lightly with salt and pepper.
Step 2: Make the filling. In a medium bowl, combine the softened cream cheese, minced garlic, chopped parsley, chopped chives, onion powder, and black pepper. Mix until well combined and smooth.
Step 3: Stuff the chicken. Lay a pounded chicken breast flat. Spread about 2-3 tablespoons of the cream cheese mixture evenly over one side of the chicken, leaving a small border. Carefully roll the chicken breast tightly from one end to the other. Repeat with remaining chicken breasts and filling. Secure with toothpicks if necessary.
Step 4: Sear the chicken. Heat olive oil in a large oven-safe skillet (cast iron or stainless steel works best) over medium-high heat. Once hot, carefully place the stuffed chicken breasts, seam-side down, into the skillet. Sear for 3-4 minutes per side, until golden brown all over.
Step 5: Bake to perfection. Transfer the skillet to a preheated oven at 375°F (190°C). Bake for 18-22 minutes, or until the internal temperature of the thickest part of the chicken reaches 165°F (74°C). If desired, add 1/2 cup chicken broth to the pan before baking for a light pan sauce.
Step 6: Rest and serve. Remove the skillet from the oven. Carefully remove any toothpicks. Let the chicken rest for 5-10 minutes before slicing and serving. This allows the juices to redistribute, ensuring a tender and moist result. Drizzle with any pan sauce, if using.