1Step 1
- Marinate the mushrooms. In a shallow dish, whisk together balsamic vinegar, olive oil, garlic, herbs, salt, and pepper. Add mushrooms, cap side down, and flip to coat. Marinate 30-120 minutes in the fridge.
2Step 2
- Preheat the grill. Heat to medium-high (400–425°F). Clean and oil the grates.
3Step 3
- Grill the mushrooms. Place mushrooms cap side down and cook for 5 minutes. Flip and cook for another 4–5 minutes until tender and charred at the edges. Remove from heat.
4Step 4
- Toast the buns. Lightly brush cut side of buns with olive oil and toast directly on the grill until golden.
5Step 5
- Assemble the burger. On bottom bun: optional smear of Boursin cheese, grilled mushroom, arugula, red onion, and roasted pepper. Top with bun.