Step 1

In a large bowl, whisk together the olive oil, balsamic vinegar, Italian seasoning and garlic powder. Add the portobello mushrooms to the bowl and gently toss with the marinade, then season with salt and pepper. Use a brush to coat the marinade all over the mushrooms.

Step 2

Preheat grill or grill pan to medium heat. Coat grill grates with olive oil.

Step 3

Place the mushrooms on the grill in a single layer cap side down. Grill for 8 minutes, then flip over and grill until knife tender and caramelized, about 4-6 more minutes.

Step 4

Serve immediately with fresh parsley, if desired.