Heat a large skillet over medium-high heat. Add 1 tablespoon of the oil to the pan and swirl it around to coat. Sprinkle chicken with ¼ teaspoon salt and pepper. Add chicken to the pan and cook for about 7 minutes per side, or until cooked through and golden brown. Remove chicken from skillet and set aside on a plate. Cover with foil to keep warm.

Do not clean out the skillet, but add another 1 ½ teaspoons oil. Add onion and rosemary; cook for 1 minute or until lightly golden, scraping up the bits from the bottom of the skillet as you stir. Add brown sugar, vinegar, mustard, ¼ teaspoon salt, and peaches; cook 12 minutes or until peaches are softened. Add the Big Peach