Preheat oven to 350°F. Cut a pocket about 3/4 quarter of the way through on the thickest side of each breast, being careful not to cut all the way.
Season chicken with salt, pepper, oregano, Tuscan herb and basil olive oils. Pour 1 teaspoon of sun dried tomato oil over each breast, rubbing some of the seasoning inside the pockets.
Fill each with 2 slices fresh tomato, 2 teaspoons sun dried tomato strips, one slice mozzarella cheese and basil leaves.
Seal with 3-4 toothpicks to keep the filling inside while cooking.
Heat 2 teaspoons of garlic olive oil (or plain extra virgin olive oil) in a skillet or non stick pan over medium-high heat. Add the chicken and fry for 2 minutes on each side until golden.
Quickly, while the chicken is cooking, mix together the garlic, balsamic vinegar and brown sugar in a small jug. Lower the heat to medium, Pour the mixture into the pan around the chicken; bring to a simmer while stirring occasionally, until the glaze has slightly thickened (about 2-3 minutes).
Transfer pan to the preheated oven and continue to cook for a further 15-20 minutes (might be longer depending on the thickness of the chicken), or until the chicken is cooked through and the cheese has melted. Could be a little longer than 20 minutes.
Remove toothpicks and drizzle with extra balsamic vinegar.