First, butterfly the chicken breasts. This involves slicing them almost through, creating a pocket. Then, season each breast with a pinch of sea salt and white pepper.

Next, place a slice of prosciutto and about two tablespoons of shredded Fontina cheese inside each chicken breast. Fold them over to seal the stuffing inside.

In a sauté pan, melt the clarified butter over medium heat. Add the finely diced sweet onion, sliced cremini mushrooms, and minced garlic. Sauté until they are tender and fragrant.

Use the same pan or a new one with a bit of clarified butter. Cook the stuffed chicken breasts over medium heat until they are golden brown on both sides. This should take about 5-7 minutes per side.

In the same pan, add the white wine, lemon juice, and chopped capers. Let it simmer and reduce slightly. Then, add the unsalted butter, stirring until it melts and the sauce thickens.

Add the fresh thyme leaves and basil to the sauce. Pour it over the chicken breasts. Let everything simmer together for a few minutes until well combined.