The perfect portobello is grilled hands down. Even meat lovers learn to love these mushrooms. They work excellent in burgers, sandwiches, pizzas etc. I make mine simply by marinating them in Italian dressing and tossing them on the grill. The photo is of portobellos and grilled green beans. See recipe for green beans here.
I started with three MASSIVE mushrooms, might I add, that I got at our grocery store.
Toss the sliced mushrooms with 1 cup of italian dressing, recipe found here. And now for a montage of tossing mushrooms.
Throw the mushrooms onto a very hot grill. Cook for about 5-10 minutes and flip occasionally until mushrooms are tender.