Preheat the oven to 375°F and lightly grease a 9x13-inch glass baking dish with cooking spray or oil.

Pat the chicken breasts dry with paper towels and arrange them in a single layer in the prepared dish, gently pounding any especially thick ends to an even thickness.

Pour the condensed French onion soup evenly over and around the chicken, nudging some underneath the pieces with a spoon.

Cover the dish tightly with foil and bake for 20 to 25 minutes, until the soup is bubbling around the edges and the chicken is mostly cooked through.

Carefully remove the foil and check the thickest chicken breast with an instant-read thermometer; it should read at least 150°F at this point.

Lay the provolone slices over the hot chicken, overlapping them as needed so each breast is covered.

Sprinkle the crispy fried onions evenly over the provolone, covering the top well.

Return the dish to the oven uncovered and bake for another 10 to 15 minutes, until the cheese is melted and bubbling, the fried onions are deep golden brown and crisp, and the thickest part of the chicken reaches 165°F; broil on high for 1 to 2 minutes if the onions need more color.

Let the French onion chicken rest in the hot dish for 5 minutes, then spoon the onion-rich sauce over each piece and serve with mashed potatoes, rice pilaf, or buttered egg noodles.