Ember-Roasted Corn on the Cob

Gently pull husks away from corn (do not detach from cob); remove silk. Pull husks up over corn to cover kernels. Secure husks tightly with string or a strip of foil. Soak in a large pot of room-temperature water for at least 15 minutes and up to 1 hour. Meanwhile, remove grill grate and build a hot fire in a charcoal grill, allowing fire to burn down until coals are completely covered with ash (or use the ash-covered coals remaining after grilling a main course). Push coals to one side of grill. Arrange 3 ears of corn in a single layer on cleared side of grill; cover corn with coals. Repeat on the other side with remaining coals and corn, spreading coals evenly over corn. Roast corn until most of the kernels are deep golden brown, about 10 minutes (some kernels will be flecked with dark brown spots). Remove husks; use a pastry brush to flick off any ashes. Serve with butter and salt.