Preheat oven to 375°F.
Season the chicken breasts with salt and pepper to taste.
4 boneless, skinless chicken breasts, Kosher salt and freshly ground black pepper
Wrap each piece of chicken with a slice of prosciutto, pushing down the edges to adhere.
4 slices prosciutto
Heat the butter and ½ tablespoon oil in a 10-inch skillet set over medium-high heat. Swirl the mixture around in order to coat the entire base of the skillet.
3 tablespoons salted butter, 1 tablespoon olive oil
Add the chicken breasts to the skillet and cook for 3-4 minutes on each side, depending on thickness. You want the chicken to be browned on both sides and nearly cooked through. Remove from the skillet and set aside.
Add the remaining olive oil to the skillet and sauté the garlic for 2-3 minutes, or until fragrant and translucent. Scrape the brown bits in the pan to the center as you cook, that's where all the flavor is.
3 cloves garlic
Add the cooking sherry to the skillet and bring to a boil. Reduce to a simmer and whisk in the sour cream 1 cup at a time, until the cream sauce forms. Lay the rosemary into the skillet. Let simmer for 10 minutes.
1 cup cooking sherry, 2 cups low-fat sour cream
Place the chicken back into the skillet, nestled in the sauce.
Bake, uncovered, for 5-10 minutes or until chicken is fully cooked and heated through.
Serve with rice, pasta, or on its own, spooning the sauce over the chicken.
2 sprigs fresh rosemary, Freshly shredded Parmesan cheese