These Portobello Burgers with Swiss Cheese and Avocado are a delicious and healthy alternative to traditional beef burgers. The meaty portobello mushrooms are marinated in a flavorful mixture of balsamic vinegar, soy sauce, and garlic, then grilled to perfection. Topped with melted Swiss cheese and creamy avocado slices, these burgers are packed with flavor and texture. Serve them on a toasted bun with your favorite condiments and enjoy a satisfying and nutritious meal.