how to grill a portabella mushroom

how to cook everything suggested making a basting sauce of olive oil, onion or shallot and salt and pepper and to grill the mushroom until it was brown, about 5 minutes per side. i used the high setting on a gas grill and started with the cap side on top. i lavishly basted the mushroom when i put it on the grill and when i flipped it. i didn't see the mushroom change color, but after 5 minutes on each side, it started to drip, which made a lot of noise as the fire hisses from the drips. i took it off the heat about a minute after it started hissing, and it was fabulous. it was obviously cooked, but still incredibly moist. yum. that was the first time i'd used the grill in the complex - i think it'll be happening more often.