Soak the cedar plank in water for at least 24 hours before cooking, weighing it down with cans to keep it fully submerged.
Start your barbecue and heat it to high temperature.
Rub the salmon fillets all over with the garlic-infused olive oil.
Sprinkle each fillet with chopped shallots and top with fresh dill sprigs.
Squeeze lemon juice over each fillet and finish with crushed black and pink peppercorns.
Place the soaked plank on the BBQ and sprinkle with coarse salt.
Close the cover for 2 minutes or until the top of the plank is nearly dry.
Place the seasoned salmon fillets on top of the plank.
If using a two-burner BBQ, turn off the burner beneath the plank. For single burner, reduce heat to lowest setting.
Close the cover and cook for 10-12 minutes until fish is nearly cooked through.
Squeeze additional lemon juice over the cooked salmon before serving.