Preheat frying pan over medium heat. Wrap each chicken breast in a piece of prosciutto.
Pan-sear two or three pieces at a time until golden.
Transfer to a large baking dish. Top with the sliced mozzarella. Bake for 20-25 minutes or until the chicken reads 160 degrees when checked with a meat thermometer.
Meanwhile, add the garlic to the pan. Cook for 1-2 minutes or until softened. Add the broth to the pan and turn up the heat. Scrap any browned bits off the bottom. They give the sauce tons of flavor.
Mix the xanthan gum into the lemon juice and add that to the frying pan. Cook until slightly thickened. Turn to very low. Season to taste.
When the chicken is cooked through spoon the sauce on top of it and serve.