Fontina and Prosciutto—Stuffed Chicken Breasts with Radicchio-Fennel Sauté

When a chicken is stripped of its bones and skin, a great way to dress it back up is to stuff it with something delicious. Cheese and ham come directly to mind . . . namely, fontina cheese, which gets all oozy and soft when melted, and prosciutto, the prized Italian cured ham, for its blast of rich, smoky flavor. So—now that the chicken is all taken care of, let’s turn our attention to the vegetables. I can’t think of anything I’d rather eat with a luscious stuffed breast than sautéed bitte