- Combine 3 tablespoon olive oil, balsamic vinegar, Wright’s® Liquid Smoke, garlic and thyme. Brush all over mushrooms and let stand 30 minutes.
- Meanwhile, heat remaining 2 tablespoons olive oil in large nonstick skillet. Add onion and salt and cook over medium-low heat, 20 minutes, stirring occasionally or until onions are very tender and golden.
- Cook mushrooms on hot grill pan, 10 minutes, turning once or until tender. Top each mushroom with cheese slice. Cover and cook 1 minute or until melted.
- Serve mushrooms on toasted buns and top with arugula and onions. Garnish with additional thyme if desired.
Tip: To make Mushroom Sliders, use 8 to 12 large baby bella mushrooms and serve on slider buns.