01 - Preheat the oven to 400°F (200°C). Position the rack in the center.
02 - Place chicken breasts between sheets of parchment paper and gently pound with a meat mallet to an even thickness of about ½ inch. Season both sides generously with salt and black pepper.
03 - Dredge each seasoned chicken breast in all-purpose flour, shaking off any excess to ensure a light, even coating.
04 - Heat olive oil in a large oven-safe skillet over medium-high heat. Sear the chicken breasts for 2 to 3 minutes per side until lightly golden. Remove from the skillet and set aside on a plate.
05 - In the same skillet, add the finely chopped shallot and minced garlic. Sauté until fragrant, about 1 minute. Deglaze the pan with dry white wine, scraping up any browned bits from the bottom. Stir in the crushed tomatoes, chicken broth, and dried oregano. Let the sauce simmer for 5 minutes to develop flavor.
06 - Nestle the seared chicken breasts back into the simmering sauce. Top each breast with one slice of prosciutto di Parma, followed by a generous layer of sliced Fontina cheese.
07 - Transfer the skillet to the preheated oven. Bake for 10 to 12 minutes, until the cheese is fully melted and bubbly and the chicken registers an internal temperature of 165°F.
08 - Remove from the oven and garnish with fresh basil leaves. Serve immediately, spooning extra sauce over each portion.