To prepare the corn, carefully peel back the husk without removing it completely and tear off the silky threads. Gently fold the husk back over the corn. Fill a large bowl or pot with cold water and soak the de-silked corn for 15-30 minutes.
Preheat your grill to medium-high heat. Place the corn (still in it’s husk) on the grill and cook the corn, flipping it when each side turns black and charred. The whole grilling process should take about 8-10 minutes (depending on the heat of your grill). The corn husks will get awfully black but don’t worry about that. If you are worried about whether the corn is done, using an oven mitt or something else to protect your hands, pull back the husk and gently cut off a piece of the corn to test it.
When the corn is juicy and cooked, cut the kernels off the cob (again, using an oven mitt or towel to hold the hot corn while you cut off the kernels). Toss the hot corn with the butter. Stir in the cumin, salt, pepper and green onions. Serve immediately.