Place cedar planks into a roasting pan big enough to easily fit the plank. Add water to cover the cedar plank completely and place something on top to keep it submerged. Make sure it’s fully submerged in water and soak for 1-2 hours.
Prepare the salmon:
Rub bottom of the salmon skin with some oil.
Season the salmon with salt and pepper evenly and sprinkle the brown sugar evenly. Sprinkle some cayenne pepper if using. Pat the seasoning into the salmon. (Don't rub!) Set it aside until ready to put on the plank to grill.
Grill the salmon:
Preheat the grill to medium heat (about 450°) with a two-zone fire just in case. Place salmon onto the soaked wood planks. Place the wood plank with salmon onto the grill over direct heat.
Close the lid and cook salmon until it’s done. I prefer to cook it until it reaches 135° in the thickest part. (Use an instant read meat thermometer to check the internal temperature of the salmon.)
(Note: USDA recommends salmon safe temperature to be 145° but many people feel that it is overdone.) Depending on the thickness of salmon piece, it could take from 12-20 minutes. A whole salmon filet that is thick could take well over 20 minutes. You will have to check the temperature with an instant read thermometer.
Notes
Soaking wood planks: You have to soak the wood planks before grilling! Make sure it’s fully submerged in water and soak for 1-2 hours.Temperature of the grill: The temperature of the grill should be medium – a medium grilling temperature is between 350° and 450°F.Time to cook salmon: Depending on the thickness of salmon piece, it could take from 12-20 minutes. A whole salmon filet that is thick could take well over 20 minutes. The best way to check your meat temperature is always to use an instant read thermometer.