Mix all ingredients up and marinate portobella mushrooms for 15-30 minutes, then grill.
Stacy's Notes - Made May 2003 - very very good! Even Tim likes these. I had 4 nice size portobellinis (baby portabellas) and made the full recipe for marinade, which was way too much. Scale back next time. Used 2 or 3 good sized cloves and just eyeballed the basil and oregano (used dried). Can either grill on outdoor grill or the GF grill. Very juicy and flavorful. Definite keeper!