1. Fire up grill. Place grill basket with fine holes directly on coals to preheat for 3 minutes.
2. Add corn and half of torn basil to hot basket and season with salt. Roast directly on coals until the kernels start to char, 3-5 minutes. (For gas grill, cook in basket on grates over high heat for 8-10 minutes.)
3. Transfer corn to large metal mixing bowl. Toss with butter (it will melt from the residual heat of the corn), remaining torn basil, lime zest, and juice. Add more salt to taste.