1. Combine all ingredients (except the mushrooms). Let the oil mix sit to absorb all the flavors.
2. Spoon oil mixture spreading evenly on underside of each cap and let soak. Make sure to reserve enough to brush on top of cap.
3Grill on high. Grill with underside down, and baste top with remaining oil mix. When underside is well done (nearly charred – about 4-5 minutes) flip over and grill again for same length of time.