Separate dough into 5 biscuits; cut each biscuit into quarters. Set aside. In 3-quart saucepan, stir gravy and cornstarch with wire whisk. Stir in milk, thyme, pepper, chicken, vegetables and potatoes. Heat to boiling over medium-high heat, stirring occasionally. Immediately spoon about 1 cup hot chicken mixture into each ramekin; top each with 4 biscuit pieces.