* Prepare grill. Open each of 8 (8-ounce) dressed whole rainbow trout as you would a book. Sprinkle 1 teaspoon kosher salt and 1/2 teaspoon freshly ground black pepper evenly over fish. Arrange 3 (1/4-inch) lemon slices and 1 thyme sprig onto bottom half of each fish; fold over to cover with top half of fish. Place on a grill rack coated with cooking spray; grill 2 minutes on each side or until fish flakes easily when tested with a fork or until desired degree of doneness. Garnish with additional thyme sprigs, if desired.