Directions

1. Clean mushrooms with a damp cloth; remove stems. Soak mushrooms in 4 cups hot water 15 minutes. Drain, gill side down, on paper towels.
2. Place mushrooms, gill side up, in a glass dish. Drizzle with oil and vinegar; refrigerate 1 hour.
3. In a small bowl combine feta, lemon juice, oregano, onion and olives. Set aside.
4. Preheat grill to medium (300°F to 350°F). Remove mushrooms from marinade. Place mushrooms on grill, gill side down. Grill 3 to 4 minutes or until lightly charred; turn and grill 3 to 4 minutes more. Remove from grill.
5. Fill mushrooms with feta mixture. Place back on grill. Grill, covered, 5 minutes or until cheese melts. Serve hot.