In a large pot, brown the onion and sausage meat in the butter, breaking the meat up with a wooden spoon. Add the ham and garlic and continue cooking for 1 to 2 minutes. Add the wine, mussels, parsley and breadcrumbs and stir to combine.
Cover and continue cooking, stirring frequently until the mussels open, about 4 to 5 minutes. Discard any mussels that remain closed. Season with pepper. Serve with oven-baked fries, if desired.