Season the chicken with salt and pepper. Place the flour, garlic powder, onion powder and paprika in a rimmed dish for dredging. Dredge the chicken through the flour and coat on both sides. Shake off an excess.
Lay prosciutto in a cast iron skillet on medium heat and cook until crispy on all sides. (Add drop of oil if pan gets too dry.)
In the same skillet, add 2 tablespoons butter and 3 chicken breasts. Sear on both sides until golden and remove to a plate. Repeat with the rest of the chicken.
Add the mushrooms. Cook undisturbed until golden about 5 mins.
Add the last 2 tablespoons butter, the shallots, sage, and a pinch each of salt and pepper. Add olive oil if needed. Cook for 5 minutes, until the mushrooms have caramelized.
Add the wine, then the broth. Simmer for 5 minutes, add in the cream and cheese.
Return chicken to the skillet. Simmer on low a few mins to finish cooking the chicken through. Top with the crispy prosciutto and parsley.
Add cooked/buttered shells to the skillet