Preheat the oven to 350 degrees F.
Place the corn, in its husks, directly on the oven rack and roast
for 20 minutes until the corn is soft when you press on it.
To finish off the corn
down the husks, remove the corn silk, and tie the husks in a knot so you can hold on to it like a handle. Char
the corn on a hot grill
, over a gas flame, or under a broiler, until the kernels are slightly blackened
all around and start popping, about 6 minutes. Rub the corn with mayonnaise, sprinkle with Parmesan
and cayenne pepper
so it's nicely coated. Serve with lime