Place the corn in its husks directly on the oven rack and roast until the corn is soft when you press on it, 30 to 40 minutes.
While the corn is roasting, combine the butter with the chili powder and lime zest.
Peel down the husks and tie in a knot to use as a handle while eating. Rub the corn with soft butter mixture, and garnish with a lime wedge. (This roasting method produces the sweetest corn I have ever tasted.)