Fat's browning effect, its ability to transfer heat and, perhaps most importantly, its flavor make it a superior cooking medium. Pure fats such as oil, make lean meats such as skinless chicken breasts more palatable by lubricating the protein fibers and improving their texture. However, you can cook a chicken breast in the oven without oil or any added fat without sacrificing much flavor by braising it. Although commonly used for tough cuts of lean meat, braising skinless chicken breasts in broth creates moisture that prevents them from drying while bolstering their flavor.
Pat the chicken breasts dry with paper towels and trim off the cartilage. If you have a whole breast, cut out the cartilage that separates the breast lobes and discard it. You can slice the chicken into strips or small cubes, but it stays juicier if you cook it whole and slice it after.
Season the breasts on all sides with kosher salt and black pepper.
Pour an even layer of small-diced mirepoix in the bottom of an oven-safe dish. Mirepoix, or 2 parts diced white onions to 1 part each diced carrots and celery, contributes a lot of flavor and aroma to any dish, but it stands out in those that lack the support of fat, such as dry chicken breasts.
Place the breasts on top of the vegetables and pour in enough cold chicken stock or broth to cover them by half. The broth prevents the breasts from drying out during cooking while bolstering their flavor. Starting with cold stock or broth minimizes the amount of the foam, referred to as soluble cell proteins, that collects on the surface of the liquids in which you cook chicken.
Add fresh herbs and spices of your choosing to the dish. Chicken breasts have such a mild, neutral flavor, you can't go wrong when it comes to choosing herbs and spices to add to the braising liquid.
Heat the oven to 350 degrees Fahrenheit. Wrap the dish with plastic food wrap, cover it with aluminum foil and place it in the oven.
Braise the chicken for 25 to 30 minutes per pound, or until it reaches an internal temperature of 165 F. Check the temperature of the breasts by inserting a meat thermometer in the thickest portion and waiting 10 seconds for it to register.