If you don't love blue cheese, use goat cheese (chèvre) or feta cheese for an equally delicious, tangy flavor. Gills are the brownish-black walls on the underside of mushroom caps. Scrape them off gently using a spoon. Removing gills keeps other ingredients from turning a grayish brown.
2 large portobello mushroom caps, stemmed
3 tablespoons balsamic vinegar
1 tablespoon olive oil
1 teaspoon minced fresh garlic
1/2 teaspoon pepper
1/4 teaspoon salt
1/4 cup crumbled blue cheese or Gorgonzola cheese
2 tablespoons light mayonnaise
1 teaspoon balsamic vinegar
2 whole wheat hamburger buns, split
Romaine lettuce leaves
2 tomato slices
How to Make It
Scrape gills from mushroom caps, if desired.
Combine 3 tablespoons vinegar, oil, and next 3 ingredients in a shallow dish or large zip-top plastic freezer bag; add mushrooms, turning to coat. Cover or seal, and chill 1 hour, turning occasionally. Remove mushrooms from marinade, discarding marinade.
Grill mushrooms, covered with grill lid, over medium-high heat (350° to 400°) 3 to 4 minutes on each side or until tender. Remove mushrooms from grill, and immediately sprinkle undersides evenly with blue cheese.
Stir together mayonnaise and 1 teaspoon vinegar. Spread mixture evenly on cut sides of buns; place lettuce, mushrooms, and tomato slices on bottom halves of buns, and cover with tops. Serve immediately.
Great twist! The mushrooms had tons of flavor after marinating and were tender and "meaty." I used feta, and it gave the burgers a creamy tang. My only complaint was that the balsamic mayo was a little bit too much, since there was vinegar in the marinade, too.