About an hour before serving, place the ears of corn in a deep bowl, cover with cold water and weight with a plate to keep them submerged. Light your charcoal fire and let it burn until the bed of coals is medium-hot; adjust the grill 4 inches above the fire.
Lay the corn on the grill and roast for 15 to 20 minutes, turning frequently, until the outer leaves are blackened. Remove, let cool several minutes, then remove the husks and silk. About 10 minutes before serving, brush the corn with melted butter, return to the grill and turn frequently until nicely browned. Serve right away, passing the cream, cheese and powdered chile for your guests to use to their own liking.
Traditional Variation: Fresh Corn, Fried (Esquites)
In Toluca and Mexico City the corn is occasionally prepared as follows: Cut the kernels from 6 cobs, then fry in 3 tablespoons lard or vegetables oil (or butter) with hot green chile to taste (seeded and sliced) and 2 or 3 tablespoons chopped epazote. Season with salt.