You will need:
-Cedar grilling planks (can be found at many grocery stores or your hardware stores grilling section, made specifically for cooking)
-Lemons/Limes/ Any citrus that strikes your fancy (oranges, grapefruit, etc)
-Fresh italian parsley and thyme
-S&P
-Olive oil
-Onions
-Preferably whole fish, with the skin still on it but gutted and cleaned of scales (but fillets will do as well)
preheat the grill, if your grill has more than one burner, this is perfect, leave one side off and the other on
Start out by soaking the cedar planks in water, about an hour is good but you can do it longer, hot water penetrates the wood faster
season the fish inside & out by rubbing lightly with olive oil and sprinkling with S&P, then stuff the cavity of the fish with chopped thyme and parsley
slice your onions & citrus, place a few thin slices on the board, then place the fish on top
Cover the fish with the slices of onion, lemon, lime, etc, drizzle with olive oil
Place the planks over the portion of the grill without a burner on, this is an indirect cooking method so the heat from the other burner will cook the fish more slowly, this also cuts down on flare-ups from using wood as a cooking medium, and gives the fish more time to absorb all the great flavors you are bringing together
How long this takes will depend on your grill, but its a low & slow method, burners on low, its gonna be slow, on the other hand, because of the moisture from all the onion, citrus, fresh herbs, and olive oil, this dish is very difficult to overcook, i usually check it about every half hour just to make sure all is well
When your fish is done, you can remove the cedar plank from the grill, and serve just like that, the plank makes a great presentation, and you will have everyone praising your awesome fish
(i prefer to use salmon, but im also from washington state and salmon is a staple up here, also has worked great with red snapper and sea bass, and could work with many other varieties of fish)