Preheat the grill to medium.

Remove the husks of the corn but leave the core attached at the end.

Grill the corn until slightly charred, turning while cooking so it cooks evenly.

Mix together the mayonnaise, sour cream, and cilantro.

While the corn is warm, cover with the mayonnaise mixture. Squeeze the lime juice over the corn and sprinkle with the Parmesan cheese.

Season with chili powder and serve with the lime wedges.