Creating grilled Portobello mushrooms with balsamic glaze is a straightforward process. Follow these steps to ensure perfect results:

1. Clean the Mushrooms: Gently wipe the Portobello mushrooms with a damp cloth to remove any dirt. Remove the stems.

2. Make the Glaze Marinade: In a bowl, whisk together the balsamic vinegar, olive oil, minced garlic, soy sauce, brown sugar, black pepper, and salt.

3. Marinate the Mushrooms: Place the cleaned mushrooms in a shallow dish. Pour the marinade over them, ensuring they are well-coated. Let them marinate for at least 20 minutes.

4. Preheat the Grill: While the mushrooms are marinating, preheat your grill to medium-high heat.

5. Grill the Mushrooms: Once the grill is hot, place the mushrooms cap-side down on the grill. Cook for about 5-7 minutes.

6. Turn and Baste: Flip the mushrooms and baste them with any remaining marinade. Grill for another 5-7 minutes, or until they are tender and have nice grill marks.

7. Serve: Remove the mushrooms from the grill and let them rest for a minute. Garnish with fresh herbs before serving.

8. Enjoy: Serve these grilled Portobello mushrooms with balsamic glaze as a main dish, side, or addition to salads and sandwiches.