Trim the chops, and cut horizontally through to make a pocket for the stuffing. In a skillet fry the onion in butter, add the kidneys and mushrooms, continue to cook for 5 minutes. Add the remaining ingredients except for the oil. Mix well. Press a spoonful of this mixture into the pocket of the chops. Secure with a toothpick. Brush with the oil, and grill under medium heat for 8 to 10 minutes, turning once, until done.

Enjoy!