- ¼ c. balsamic vinegar
- ¼ c. olive oil
- 3 garlic cloves, minced
- 1 tsp. salt
- ¼ tsp. crushed red pepper
- 4 portabella mushroom caps
- 2 tbsp. pesto
- 2 tbsp. mayonnaise
- 1 red bell pepper, cut in half and seeds removed
- Nonstick cooking spray
- Sprouts or watercress
- 4 brioche buns
Combine first 5 ingredients in a large zip-top plastic bag; add mushrooms. Seal and marinate at room temperature for 2 hours, turning bag occasionally. Remove mushrooms from bag; discard marinade.
In a small bowl, combine pesto and mayonnaise. Cover and refrigerate until ready to use.
Prepare grill to medium heat.
Place pepper halves on grill rack coated with cooking spray; grill 15 minutes or until blackened, turning occasionally. Remove from grill, let cool and slice into strips.
Place mushrooms, gill sides down, on grill rack coated with cooking spray; grill 4 minutes on each side. Place buns, cut sides down, on grill rack coated with cooking spray; grill 30 seconds on each side or until toasted.
Spread 1 tablespoon pesto mayo on bottom half of each bun followed by mushroom cap, a few slices of bell pepper and a heavy pinch of sprouts. Cover with top halves of buns and serve.