Place cast iron skillet on grill, close lid and heat high to hot!
Add ¼ cup extra virgin olive oil (use a good quality oil)
Throw in 4 or 5 finely chopped garlic cloves and half a chopped onion.
Brown garlic for 1 to 2 minutes stirring occasionally.
Add ½ fistful of various chopped herbs to mixture and stir. (I used cilantro, basil, sage fresh from my garden)
Add 2 pounds rinsed mussels, followed by ½ cup white wine (pinot grigio or sauvignon blanc),
Add another ½ fistful of various chopped herbs to mixture.
Add Salt and pepper.
Loosely cover the skillet with sheet of foil, close the grill lid, and cook until all mussels have opens, 5 to 7 minutes.
Serve with spaghetti and home made pesto.