I've been doing research for about a year now to figure out how to grill portabellos. I had some AMAZING ones at a barbeque a few years ago, but the event was catered, and I was too shy to ask the caterer how they made them. The feat of making amazing portabellos is doublely impressive in light of the fact that there has only been one food item that I have consistently detested and gagged on my entire life...mushrooms. After eating those, I thought that I had clearly misjudged this fungi and needed to learn more. So, after consulting allrecipes.com, foodnetwork.com, epicurious.com and several of my home cookbooks, I think I have the technique down.
Teriyaki Grilled Portabellos
4 Portabello mushrooms
1/2 cup Teriyaki sauce (I like Trader Joe's)
1. Remove the mushroom stems. They pop right out. Save them if you're ambitious and use them in homemade stock (I've only been that ambitious once).
2. Take a damp kitchen towel and wipe off the mushroom caps (don't worry about clearning the gills). If you wash mushrooms, they'll absorb the water, not the marinade.
3. Place the mushroom caps in a bowl or Ziplock bag and pour the teriyaki sauce over. Swish around to make sure the caps are completely covered. Leave at room temperature (this takes some getting used to for someone who only usually marinates meat) for about an hour.
4. Preheat grill to around 350-400 degrees or medium high if your grill doesn't have a thermometer.
5. When the temperature is right, place the mushrooms, cap side down, on the grill for 5-8 minutes. They should have some nice grill marks. Flip and continue to grill for another 5 minutes.
Honestly, I feel like the portabellos' cook time is very similar to a chicken breast's cook time. If you cook both at the same time (like I often do because most of my family still prefers chicken), they should all be done at the same time.
The portabellos are done when there's some (but not much) spongy give--like chicken breasts.
I kept hoping to be super ambitious and do a youtube video about this, but I got shy. Maybe I'll work up my courage and get a demonstration up soon.
In the meantime, I think these are a nice meat replacement. I love them in the mango summer rolls instead of chicken, or on a sandwich with other grilled vegetables and mayo.