3. Ready a medium-high fire in a grill. Remove the husks and silk, then set the corn on the grill and cook, turning frequently, until the tips of the kernels are blackened and the corn is done (to check, take a bite out of one ear, preferably the one designated for you). Brush with the melted butter and wrap them in foil to keep warm. Now grill the potato slices for about 4 minutes per side, until golden brown and crisp.