Place each chicken-breast half between 2 sheets of wax paper and pound with a meat mallet until about 3/4 inch thick

Heat the oil in a large skillet over medium-high heat. Sauté the. Hi ken until golden, about 3 mins per side

Add the apple slices, apple juice, onion, garlic, thyme, 1/2 teaspoon of salt, 1/2 teaspoon black pepper. Simmer, covered, 6 to 8 minutes, or until chicken is fork-tender.

Remove the chicken, apple slices, and onion to a serving platter and keep warm.

Bring the sauce to boil for about 5 minutes or until slightly reduced. Whisk in mustard. Pour the sauce over the chicken.