Grilled portobello mushrooms develop a meaty quality that can rival a burger. These overgrown criminis, with caps as large as 4 to 6 inches in diameter, taste great with just olive oil, salt and pepper, but also benefit from spending some time swimming in a tangy marinade before hitting the heat. Prepping the 'shrooms for the grill takes some effort, but the results are worth it.
Clean 'em Up
Washing mushrooms is generally a no-no as they soak up water and become soggy. This is especially true when you're going to toss them on the grill; sodden portobellos will steam and won't develop grill marks. Use a soft brush or a damp paper towel to rub off any dirt. Pluck the stem from the bottom and discard it. Use a spoon to scoop out the black gills; although edible, they affect the appearance of a grilled mushroom and are likely to burn during the cooking process.
Once you've cleaned the mushrooms, you can simply brush them with olive oil on both sides and sprinkle them with salt and pepper. Alternatively, marinate them in the sauce of your choice, such as Italian dressing, teriyaki sauce, balsamic vinaigrette or even barbecue sauce. They need just 15 to 20 minutes in the marinade but can stay there for a few hours if you need to get them ready ahead of time.
Get the Grill Ready
Preheat an outdoor charcoal or gas grill to medium, about 350 to 400 degrees F. Alternatively, preheat a grill pan on the stovetop, a countertop grill or a contact grill to medium heat. Pat marinated mushrooms dry and lay them on the grill. Cook them for about 5 to 6 minutes per side. Close the lid or cover the cooking mushrooms lightly with foil to help them cook through. Halfway through the cooking process, when you're ready to turn them over, brush the portobellos with additional marinade to enhance their flavor. As the mushrooms cook, they shrink slightly and take on a softer quality. The longer you cook the portobellos, the meatier their texture. Thick mushrooms may need a little extra time on the grill.
Serving the Mushrooms
Grilled portobellos are a natural for a veggie take on a burger. Serve them on a whole-grain bun or toasted sourdough with classic fixings -- including tomato, red onion and lettuce. Grilled portobellos marry well with robustly flavored cheeses, such as Gorgonzola, Gouda and Asiago. Melt the cheese into the cap while it's still on the grill by turning your mushroom stem-side up and putting the cheese in the cavity where the gills were.