On top of the cedar plank, lay a layer of greenery. Add your whole side of salmon on top of the greenery and begin to lather with oil. Season the salmon with the Garlic Herb Seasoning. Next, add your nails to secure the salmon in place. Make sure to add them along both sides in the meatier parts of the fish to be more secure.
Take your whole garlic clove and slice off the top of the head where the root is. Lather with oil and season using salt and black pepper. Completely wrap in aluminum foil.
Begin building your fire for indirect cooking. Build a fire to a medium-high temperature of about 350F. Set the fire on the far side of your grill for a two-zone indirect cooking method. Tip: build your fire next to the side of your fire pit or a wall so that the heat rises and cooks the top of the salmon as much as the bottom.
When the fire is ready, place a pole, brick or rod in the ground 2-2.5 feet away from the flames. Lean your salmon next to the pole facing the fire. Cook your salmon for about an hour or until 145F internal, flipping it about halfway through the cook. Cook it until the outside begins to caramelize and crust. If the wood or salmon begins burning, move your fire back or flip the salmon over. Prevent the plank from burning by spritzing with water when needed.
As the salmon cooks, add your garlic to the low heat coals of the fire. Move it around constantly to prevent burning. Cook for about 45 minutes to an hour or until softened.
When garlic is done, pull off fire and pull out the meat of the garlic. Mix the pressed garlic with the rest of the ingredients for the Roasted Garlic Aioli. Mix thoroughly and set aside until ready to use.
Once salmon is done, pull off and rest for 2-3 minutes. Carefully pull out the nails from the board, lather with the Roasted Garlic Aioli and enjoy!