- 4 portobello mushroom caps, cleaned
- 1/4 cup olive oil
- Salt and freshly ground black pepper
- 1/2 cup mayonnaise
- 1 tablespoon prepared pesto
- 2 teaspoons coarse-grained mustard
- 4 hamburger buns, split, buttered, and toasted
- 1 cup baby arugula
- 1 (12-ounce) jar roasted red peppers, drained
Preheat grill to medium-high heat.
Brush mushrooms caps with olive oil; sprinkle evenly with salt and pepper. Grill mushrooms, smooth side down, covered with grill lid, for 6 to 8 minutes, or until tender.
In a small bowl, combine mayonnaise, pesto, mustard, 1/4 teaspoon salt and 1/4 teaspoon pepper. Spread mixture evenly over cut sides of buns. Divide arugula evenly over bottom halves of buns. Top each evenly with peppers. Place mushrooms caps over peppers. Cover with tops of buns.