- 4 large Portobello mushroom caps
- 1/2 cup extra virgin olive oil
- 3 tablespoons aged balsamic vinegar
- 2 tablespoons spicy mustard
- 1/2 cup low-fat mayonnaise
- Salt and pepper
- 4 rolls, toasted
- Lettuce, tomato, and red onion, sliced
In a shallow dish combine the olive oil, vinegar, and mustard. Add a teaspoon each of salt and pepper and add the mushroom caps and coat with the marinade. Cover and refrigerate for 2 hours.
Remove the mushrooms from the marinade and grill or broil for 3-4 minutes per side. Meanwhile, mix 2 tablespoons of the marinade into the mayonnaise and set aside.
Schmear some of the mayo of each of the toasted buns, then top with a mushroom cap, followed by the lettuce, tomato, and red onion. Makes 4.