Creating Caprese Stuffed Balsamic Chicken is simple and straightforward. Follow these steps to make this delicious dish:

1. Preheat Oven: Preheat your oven to 375°F (190°C).
2. Prepare the Balsamic Reduction: In a small saucepan, combine balsamic vinegar and heat over medium heat. Allow it to simmer until it thickens slightly, about 5-7 minutes. Remove from heat and set aside.
3. Mix the Filling: In a bowl, combine the diced mozzarella, halved cherry tomatoes, chopped basil, minced garlic, salt, pepper, and Italian seasoning if using. Stir until well mixed.
4. Prepare the Chicken: Place each chicken breast between two sheets of plastic wrap. Use a meat mallet or rolling pin to gently pound the chicken to about ½ inch thickness.
5. Stuff the Chicken: Spoon the filling mixture onto one side of each chicken breast. Fold the chicken over to enclose the filling and secure with toothpicks if necessary.
6. Sear the Chicken: In a large skillet, heat olive oil over medium-high heat. Add the stuffed chicken breasts and sear for 3-4 minutes on each side until golden brown.
7. Transfer to Oven: Once seared, transfer the chicken to a baking dish. Drizzle the balsamic reduction over the top.
8. Bake: Place the baking dish in the preheated oven and bake for 15-20 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (74°C).
9. Rest: Once done, remove the chicken from the oven and let it rest for a few minutes before serving.
10. Slice and Serve: Carefully slice the chicken to reveal the flavorful stuffing. Drizzle additional balsamic reduction on top if desired.