Pull off the stems from the mushrooms, then marinade in tamari sauce, balsamic vinegar, minced garlic and a bit of olive oil. Marinate for at least 30 minutes. Grill on the barbeque for about 5 minutes a side. Serve on a whole wheat hamburger bun with tomato, lettuce, mayo, mustard and ketchup. For our meal we had roasted vegetables and carrot sticks with hummous.