Ingredients:
4 Portabella mushrooms
1/2 onion minced
2 cloves garlic minced
2 T. canola oil
1/4c. balsamic vinegar
Mince onions and garlic
(note: I am a sucky mincer...it's ok. also, I like garlic ALOT, maybe you might want to use just one clove)
Flip Mushrooms and pour mixture into gills. Then grill the mushrooms cap side down, don't flip them over.
Put on bun, add what you want, and eat like a burger! If you're lucky you'll find some good local corn. (from Petruzzi's in East Brookfield, in our case)