Prepare the Chicken

1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Season the Chicken: Season both sides of the chicken breasts with salt and pepper to taste.
3. Butterfly the Chicken: Carefully slice each chicken breast horizontally to create a pocket, ensuring not to cut all the way through. If needed, use a meat mallet to gently flatten the chicken to an even thickness.
4. Sear the Chicken: Heat a skillet over medium-high heat and add olive oil. Once hot, add the chicken breasts and cook for 2-3 minutes per side, just until they’re lightly golden brown. You’re not cooking them all the way through at this point, just giving them a little sear.

Make the Spinach Stuffing

1. Prepare the Filling: In a mixing bowl, combine the chopped spinach, softened cream cheese, grated Parmesan, mozzarella, minced garlic, and nutmeg (if using). Stir until the mixture is well combined. Taste and adjust seasoning with salt and pepper as needed.
2. Stuff the Chicken: Carefully stuff each chicken breast with the spinach mixture, pressing the stuffing in to ensure it’s well packed.
3. Secure the Chicken: Use toothpicks to seal the edges of the chicken breasts, holding the stuffing inside. Be sure to remove the toothpicks before serving.

Bake the Chicken

1. Transfer to Oven: Once the chicken is stuffed, place it in the preheated oven on a baking sheet or oven-safe dish.
2. Bake: Bake for 25-30 minutes, or until the chicken reaches an internal temperature of 165°F (75°C) and the stuffing is hot and bubbly.
3. Rest: Let the chicken rest for about 5 minutes before serving to allow the juices to redistribute.