Soak the cedar planks in water for at least 2 hours before you plan on cooking. You will need enough planks to cook all your salmon patties. Preheat your grill and set it up for indirect heat, at about 350-375F.

Remove the skin and any pin bones from the salmon. Cut the salmon into smaller pieces then add it to a food processor. Add the mayo, mustard, dill, salt, pepper, and garlic. Pulse until the salmon turns into a smooth paste.

Scrape the salmon paste out of the food processor and transfer it to a mixing bowl. Mix in the onion and celery.

Add the planks to the grill to allow them to preheat. Form the salmon mixture into equally sized patties. Place two on each plank then grill for about 25-30 minutes or until the salmon is fully cooked through. Remove the planks from the heat then squeeze a touch of lemon juice over the top. Serve with your favorite toppings.