Directions

1. Place steaks in a shallow dish. Brush both sides of steaks with oil and 4 tablespoons of the vinegar; sprinkle both sides with steak seasoning. Cover and refrigerate 30 minutes to 8 hours, turning once.
2. Coat grill rack with nonstick cooking spray. Preheat grill to medium-high (350°F to 400°F). Thread mushrooms onto skewers.? Drizzle with remaining 4 tablespoons vinegar, and season with salt and freshly ground black pepper to taste.
3. Remove steaks from marinade; discard marinade. Place steaks on grill. Grill, covered, 5 to 7 minutes per side or until an instant-read thermometer registers 145°F, or to desired doneness. Transfer to a serving platter.
4. Meanwhile, place mushroom skewers on grill. Grill 2 minutes per side or until tender. Top steaks with mushrooms, sprinkle with green onions and parsley, and serve.