Remove sausage casing. Mix sausage, ground meat and seasonings by hand. Mix in beaten egg. Add just enough breadcrumbs take stickiness away. Pack tightly into meatballs.*
Wash and stem shiitakes and cut onions for kabobs. Gently arrange meatballs onto skewers, supporting them well with onions and mushrooms on each side. Heat grill.
Mist kabobs with olive oil, sprinkle scantly with Tony’s Tuscan Grill Rub or seasonings of your choice. Grill over medium heat, until meatballs are done (160 degrees internal, or until no longer pink – about 15 minutes) turning gently as needed. Rest 5 minutes before serving.
*Also makes great patties for burgers.