Soak whole, unshucked ears of corn in water for a few hours or overnight. Place them over charcoal or in the ashes of a barbecue pit. Rotate the ears about every 5 minutes to avoid burning on one side. They will be ready in about 30 minutes, when the husks are beginning to scorch on all sides and the interior is steaming.

Lime Butter
3/4 cup (1 1/2 sticks) butter, softened
2 tablespoons fresh Mexican lime juice
Salt, to taste

Mash butter and lime juice together with a fork. Add salt and blend.