Preheat the oven to 400 degrees.
Slice the chicken breasts in half lengthwise, resulting in 4 thinner chicken breasts. Season both sides of chicken breasts with salt and pepper, to taste.
In a large oven-proof skillet, heat the olive oil and butter over medium-high heat. Add the chicken breasts to the skillet, careful to not overcrowd the pan. Cook each side, about 3-5 minutes.
Using a pastry brush or the back of a spoon, top each chicken breast with 2 tablespoons of prepared pesto sauce, a slice of mozzarella, and sliced tomatoes.
Place the skillet in the preheated oven. Cook for 10 minutes or until cheese has melted and the chicken has reached an internal temperature of 165 degrees on a digital instant-read thermometer.
Remove the skillet from the oven drizzle the chicken breasts balsamic glaze and garnish with fresh chopped basil. Serve immediately. Enjoy!
If you don't have balsamic glaze on hand, but you have balsamic vinegar and sweetener such as maple syrup, honey or brown sugar - you can easily prepare this delicious glaze on your stove top.
In a saucepan over medium heat, add balsamic vinegar and your sweetener of choice. Once the mixture begins to simmer, reduce the heat to medium-low. Continue to simmer until the liquid reduces by half, about 10-15 minutes. Remove the balsamic glaze from the heat and set aside to cool.