1) Get the barbecue coals to the point that white ash is showing and the coals are glowing and are spread out in an even layer.
2) Grill the corn for 12 minutes total. Continually move the corn so each side is grilled.
3) In a bowl whisk together the mayonnaise and lime juice.
4) In a separate bowl mix together the Parmesan cheese, chili powder, cayenne pepper, cumin, and salt.
5) Spread the mayonnaise mix over the corn.
6) Sprinkle the cheese mix over the corn.
7) Serve the grilled corn while it is still hot and supple. Makes an excellent side dish.