Remove the husks of the corn but leave the core connected at the end so you have something to grip onto. Grill the corn on a hot grill or cast iron griddle pan until slightly browned. Turn it so it gets cooked evenly all over.
Mix the mayonnaise, sour cream and cilantro together. Grate the Parmesan in another bowl.
While the corn is still heated slather with mayonnaise mix. Squeeze lime juice over the corn and spray with Parmesan. Season with chili powder and serve with more lime wedges.
Notes
The corn develops an amazing flavor from the slight charring. Prepared in this manner, it turns out juicy and delicious.