Preheat your grill to 400 degrees F for indirect cooking.
Carefully press the whole pineapple onto the stand of a chicken roaster. Use your hands to cover the exterior of the pineapple with the dark brown sugar. Place the roaster on the indirect side of the grill and cook for 20-25 minutes, turning as needed to prevent burning.
Remove the pineapple from the grill. Brush with the melted coconut oil and carefully press on the shredded coconut. It's OK if some falls onto the roaster.
Return to the grill for 4-5 more minutes, or until the edges of the coconut are nice and toasty.
Remove the pineapple from the roaster and slice. Sprinkle with the additional toasted coconut from the bottom of the roaster and serve immediately. It's AWESOME with coconut ice cream.