Making Grilled Portobello Mushroom Burgers is simple and straightforward. Just follow these easy steps:

1. Prepare the Marinade: In a mixing bowl, combine balsamic vinegar, olive oil, minced garlic, salt, and black pepper.
2. Marinate the Mushrooms: Place the portobello mushrooms in a shallow dish or resealable bag. Pour the marinade over the mushrooms, ensuring they are well coated. Let them marinate for at least 10 minutes.
3. Preheat the Grill: Heat your grill to medium-high heat.
4. Grill the Mushrooms: Remove the mushrooms from the marinade and place them on the grill, gill side down. Grill for about 5-7 minutes. Flip them and grill for an additional 5-7 minutes until tender.
5. Lightly Toast the Buns: Just before the mushrooms are finished, place the whole wheat buns on the grill to toast lightly.
6. Assemble the Burgers: On each toasted bun, place a grilled portobello mushroom. Top with arugula, sliced tomato, and avocado. Add any additional toppings you prefer.
7. Serve: Serve warm and enjoy your amazing grilled burgers!

By following these steps, you’ll create mouthwatering Grilled Portobello Mushroom Burgers that everyone will love.