01 - Preheat the oven to 400°F (200°C).
02 - Place chicken breasts between sheets of parchment paper and gently pound to an even thickness of about ½ inch. Season both sides generously with salt and black pepper.
03 - Dredge each chicken breast in the 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 for 2 to 3 minutes per side until lightly golden. Remove 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, stirring to prevent burning.
06 - Deglaze the pan with dry white wine, scraping up any browned bits from the bottom. Add the crushed tomatoes, chicken broth, and dried oregano. Stir to combine and simmer for 5 minutes until the sauce slightly thickens.
07 - Nestle the seared chicken breasts into the simmering sauce. Top each breast with a slice of prosciutto di Parma followed by a layer of sliced Fontina cheese.
08 - Transfer the skillet to the preheated oven and bake for 10 to 12 minutes, until the Fontina has melted and the chicken is cooked through to an internal temperature of 165°F.
09 - Remove from the oven, garnish with fresh basil leaves, and serve hot with extra sauce spooned over each portion.