bubbling around the edges. This covered step lets the chicken gently poach in the onion-rich sauce, building flavor.
Carefully remove the foil and check the thickest piece of chicken with an instant-read thermometer; it should be at least 150°F (66°C) at this stage. (It will finish cooking after the toppings go on.)
Lay the provolone slices over the hot chicken breasts, overlapping slightly as needed so each piece is completely blanketed in cheese. The cheese should cover most of the exposed soup surface as well, which helps it
