Place the chicken on a chopping board and with a sharp knife, carefully slice into the side of the chicken breast, creating a deep pocket for the stuffing.
Place a few tablespoons of shredded/grated mozzarella, sundried tomatoes and a basil leaf in each chicken breast. Secure the opening with toothpicks.
Season generously with salt, pepper and Italian herbs.
Add a few tablespoons of olive oil to a large oven-proof frying pan or skillet and heat over medium-high heat.
Add the chicken breasts and brown on both sides then pour the Balsamic vinegar over the chicken. Place in the oven and allow to cook for 15 minutes or until cooked through.
Remove from the pan and allow to rest for 5 minutes before serving.