Grilled Portobello Burgers

In '1,000 Vegan Recipes' by Robin Robertson

• Ready In: 25 mins
• Serves: 4

Ingredients

• 2  tablespoons olive oil
• 1  tablespoon  balsamic vinegar
• 1⁄4 teaspoon sugar
• 1⁄4 teaspoon salt
• 1⁄8 teaspoon fresh ground black pepper
• 4  large  portobello mushroom caps, lightly rinsed and patted dry
• 4  slices red onions
• 4  kaiser rolls, halved horizontally
• 8  large fresh basil leaves
• 4  slices  ripe tomatoes

Directions

1. Preheat the grill or broiler.
2. In a small bowl, combine the oil, vinegar, sugar, salt, and pepper; set aside.
3. Place the mushroom caps and onion slices on the hot grill and cook until grilled on both sides, turning once, about 10 minutes total.
4. Brush the tops of the mushrooms and onion with the vinaigrette and keep warm.
5. Place the rolls cut side down on the grill and lightly toast, about 1 minute.
6. Layer an onion slice and mushroom onto the bottom half of each roll.
7. Top each with two basil leaves and a tomato slice.
8. Drizzle with any remaining vinaigrette and cover each burger with the roll tops.
9. Serve immediately.