2 untreated cedar or alder planks, 3/4-inch thick and 12 to 15 inches long
Place the planks into cool water and allow to soak for at least 2 hours and up to overnight.
Preheat the grill to 375 to 400 degrees F.
Brush the trout, inside and out with olive oil. Season inside and out with salt and pepper. Place the trout onto the planks belly down and open. Place the planks over indirect heat and grill until the fish reaches an internal temperature of 120 degrees F on an instant-read thermometer, approximately 15 to 20 minutes. Remove from the grill and allow to sit for 5 to 10 minutes before serving as is or deboning and serving.