Combine all of the bourbon sauce ingredients in a bowl and stir to combine.
Place the salmon filets in a large resealable bag and pour half of the sauce over top, then toss to coat and refrigerate. Let marinate for at least 30 minutes, turning occasionally. Reserve the remaining sauce for later.
Preheat your grill for two zone cooking with one side medium heat and the other side high heat.
While the grill preheats, add the reserved bourbon sauce to a small saucepan set over medium heat. Bring the sauce to a boil, then reduce heat to maintain a rapid simmer. Cook for 3-4 minutes, until the mixture is reduced by around half, stirring frequently to avoid foaming over. Remove from heat and let cool for a few minutes to thicken.
Place the salmon filets on your cedar plank skin side down and add to the grill on the medium heat side. Cover the grill and cook for 10 minutes.
Open the grill and baste the salmon with the bourbon glaze. Cook for another 5-10 minutes, basting occasionally with the remaining glaze, until the salmon reaches your desired doneness.