Soak two cedar planks and soak them in water 60 minutes. Pre-heat big green egg to 350. Place cedar planks on big green egg for four minutes when temps tire of egg reaches 350. Flip cedar planks and coat the top of the planks with olive oil. Add two salmon filets on each cedar plank and cook for 20 mins. Start checking salmon for flaking at minute 17. Remove from planks, place in pan then add fresh lemon and melted butter on top of the salmon.