Preheat an outdoor grill for high heat. Soak desired amount of corn in cold water for 10 minutes (with husks still on).
Put on a hot grill in the husk. Cook for 10 minutes, turning occasionally; remove the corn from the grill and set aside for 5 minutes. Once the husk has cooled slightly, carefully pull back the charred husk and grill for an additional 5 minutes, turning frequently.
Serve with butter or sprinkle with parmesan cheese.