Ingredients:

1/2 C. of your favorite single varietal extra virgin olive oil
1/2 C. barrel aged red wine vinegar
2 cloves garlic, minced
1/4 tsp. red pepper flakes
1/2 tsp. onion powder
1/2 tsp. oregano
1/2 tsp. salt

Instructions:

To make the marinade for the mushrooms mix extra virgin olive oil  and red wine vinegar. Add minced garlic, red pepper flakes, onion powder, and oregano. Put this into a food storage bag. Thread each mushroom onto a sprig of rosemary (spearing the mushroom first with a wooden skewer makes it easier). Place mushrooms in a bag to marinate. Then you can just grab and go, grilling the mushrooms on site.