Thirty minutes before cooking, combine 2 tablespoons of water with 2 tablespoons of Ardbeg Scotch and place into a small spray bottle. Spray the cooking side of the cedar plank with the mixture. Do this a few times if needed. Let the plank dry on a clean surface.
Preheat grill for medium-high heat.
Combine the juice of 1 lemon with 2 tablespoons Ardbeg and the olive oil. Slice the other lemon into 3-4 slices, discarding the ends. Submerge slices into the mixture for 1 minute to absorb the scotch flavor. Remove and place slices onto a clean plate.
Meanwhile, place salmon, skin side down, onto Scotch treated cedar plank. Brush the salmon with the same mixture used for the sliced lemons—season with salt, black pepper, garlic powder, and rosemary. Arrange the lemon slices on top of the filet.
Place planked salmon in the grill and close the lid. Let it cook until the internal temperature at the thickest part of the salmon reaches 145 degrees F. If you'd like to impart more scotch flavor, lightly brush the salmon with a bit of extra lemon-scotch mixture as it cooks. Please do not overdo it. Make sure to stop at least 5 minutes before the fish is done.
Once cooked, remove plank with fish from the grill and place it onto a heat-resistant surface. Let salmon rest for a few minutes while you get your sides ready. Serve as an appetizer with small pieces of toast, capers, and red onions, or enjoy as a main course with your favorite grilled vegetables. Remember that the scotch flavor will be subtle, but this salmon will work beautifully paired with a few sips of Ardbeg.
*Add a little finishing salt, like flaked salt, right before serving.
*As mentioned, we developed this recipe using Ardbeg scotch and cannot comment on a scotch substitution. Each brand has a unique flavor profile that may or may not be suited for fish. Please keep this in mind.