I’ve been shopping at Costco for at least a dozen years now, and they’ve always carried domestic white mushrooms. Recently they added creminis, also known as baby bella mushrooms. But the other day  I noticed portabello mushrooms finally made their debut.

Costco is my culinary barometer. When they start carrying something, I consider it mainstream. So why have portabello mushrooms gone big? I’d like to attribute their increased popularity to our reduced meat consumption.

Portabellos are the ultimate simple meatless burger. These gigantic mushrooms even look like a big burger. Plus there’s nothing to chop, mix, mash, or pat. Simply remove the stems, brush with a little oil–a little minced garlic adds big flavor here–sprinkle with salt and pepper, and they’re ready for the grill. When grilling a portabello mushroom, start them gill side down to cook out some of the moisture before turning and topping them.

Like any good burger, a portabello takes well to many seasoning and flavorings. Since we’re decidedly in summer, I took mine the tomato, basil, mozzarella direction, but during the cooler months I could get equally excited about caramelized onion and blue cheese. But let’s not get ahead of ourselves.

You’re likely to fire up the grill at some point this week. If not this week, surely the next for July 4th. Pick up some ground beef for the meat lovers in your life, but reach for a package of portabellos too. Grill up a few of both and let them taste compare for themselves. I’m betting you’ll make a few converts.

Grilled Portabello Burgers With Tomato, Pesto, and Mozzarella
Serves 4

2 tablespoons olive oil
2 medium garlic cloves, minced and divided
4 large portabello mushrooms, stems removed
Salt and ground black pepper
1 medium tomato, cut into 4 slices and lightly salted
1/4 cup prepared pesto
3 ounces thinly sliced mozzarella cheese

About 20 minutes before serving, heat all burners of a gas grill on high. Use a wire brush to clean grill rack, then use tongs to wipe an oil-soaked rag over it. Close lid and return to temperature. Alternatively, build a hot charcoal fire.

Meanwhile, mix oil and garlic in a small bowl; brush mushroom cap bottoms with the oil and sprinkle with salt and pepper. Turn mushrooms, gill side up, and repeat.

Place mushrooms on hot grill rack, gill side down; cover and grill until spotty brown, about 3 minutes. Turn mushrooms, gill side up, turn grill to low heat. Top each with a tomato slice and a portion of pesto and cheese. Place buns, cut side down, on grill rack and grill until cheese melts and bus are warm and spotty brown and warm, about 3 minutes longer.