In a small bowl combine all the butter ingredients and mash together with a fork to mix well. Place the butter on a piece of plastic wrap. Roll up the plastic to form the butter into a cylinder, (1 to 1¼ inch) thick in diameter. Refrigerate for at least 1 hour to firm up. Cut into (1/2 inch) disks and bring to room temperature before serving.
In a rectangular baking dish filled with water, submerge the cedar plank. Weigh the plank down with cans and let soak for at least 1 hour.
In a small bowl combine all the oil ingredients.
Place the salmon, skin side down, on a work surface. Score the salmon without piercing the skin into 4 serving pieces. Brush the salmon flesh with about three-quarters of the oil.
Prepare the grill for direct cooking over medium-high heat (475° to 525°F).
Prepare the grill for cooking over medium-high heat (500°F).
Brush the cooking grates clean. Drain the cedar plank. Place it over direct heat and close the lid. When the plank begins to smoke and toast, after 3 to 10 minutes, use long-handled tongs to turn it over. Slide the salmon, skin-side down, onto the toasted side of the plank. Arrange the lemon slices over the salmon and lightly brush the slices with the remaining oil.
Brush the cooking grates clean. Drain the cedar plank. Place it over medium-high heat and close the lid. When the plank begins to smoke and toast, after 3 to 10 minutes, use long-handled tongs to turn it over. Slide the salmon, skin-side down, onto the toasted side of the plank. Arrange the lemon slices over the salmon and lightly brush the slices with the remaining oil.
Grill over direct medium-high heat, with the lid closed, until an instant read thermometer inserted in the thickest part of the salmon registers 125° to 130°F (or your preferred doneness), 15 to 30 minutes for medium-rare, depending on the thickness.
Grill over medium-high heat, with the lid closed, until the thickest part of the salmon registers 125° to 130°F (or your preferred doneness), 15 to 30 minutes for medium-rare, depending on the thickness.
To serve, transfer the fillet on the plank to a heatproof surface. Lift the portions from the skin and serve with the lemons and a few pads of lemon butter.
