This is a quick, easy, and light alternative to the regular beef burger. Many meat eaters I know love these! Can be topped with mayo, tomatoes, and shredded old Cheddar or Monterey Jack cheese. I prefer to top them with roasted red peppers and goat cheese.
Preheat grill for medium-high heat and lightly oil the grate.
Whisk olive oil, balsamic vinegar, Dijon mustard, garlic, Worcestershire sauce, salt, and pepper in a bowl. Brush the mixture over the tops and bottoms of the mushrooms; let stand for 10 minutes.
Grill mushrooms on the preheated grill with the cover closed until mushrooms are browned and tender, about 10 minutes, turning once. Serve on kaiser rolls.
Per Serving: 188 calories; protein 4.1g; carbohydrates 23.7g; fat 8.5g; sodium 320.6mg.