Pescado a la Talla

Boil the chiles in a pot with the water until tender.

Transfer chiles to a blender along with most of the boiling liquid, the vinegar, garlic, onion, 1/4 tsp. of the salt, cumin, and pepper. Process to form a sauce, adding additional boiling liquid as needed.

Heat the oil in a pan over medium heat. Pour the sauce in the pan to fry, and continue to cook until thickened slightly.

Sprinkle the fish with the remaining salt and coat the flesh side of the fish with the prepared chile sauce. Grill skin-down over indirect.

Brush the top of the fish with butter and gently flip. Continue cooking until done.