Heat grill to 300˚F.
Clean fish (butterflied with head intact) or fillet. Slice butter and allow it to get to room temperature. Smear on the bone side of butterflied fish.
Place onions, celery, carrots, cilantro, and lemon on top of butter.
Take adobo (1 tablespoon) and sprinkle half on vegetables and half on the fish.
Sprinkle adobo (1/2 teaspoon) on each side of the fish.
Close fish with toothpicks and wrap in foil.
Tip: Baste fish with 2 slices of lemon, ½ stick of butter, and 2 tablespoons of lemon pepper seasoning.
Sit on bottom part of the grill to melt and baste fish when it is being checked on throughout duration of grilling.