1. Combine mustard through lime zest in a small bowl. 2. Pour over the trout fillets. Marinate in the refrigerator for 30 minutes. 3. Prepare grill to 350-400 degrees. 4. Place soaked plank on grill grates and close lid. 5. Heat plank for two to three minutes or until a light smoke develops. 6. Flip plank and place fish on heated side of plank (reserve remaining marinade.) 7. Grill with lid closed for five to eight minutes. 8. Open lid and drizzle with remaining marinade. 9. Close lid and continue to cook for an additional five to eight minutes or until trout is medium done.
