For a hearty and satisfying veggie sandwich, try this grilled portobello mushroom burger. Marinate portobello mushroom caps in a mixture of balsamic vinegar, soy sauce, garlic, and herbs. Grill the mushrooms until they are tender and juicy. Place the mushrooms on a toasted bun and top them with caramelized onions, melted Swiss cheese, and a dollop of tangy Dijon mustard. This burger will make you forget about meat.
