I don't grow sweet corn; I grow field corn, the kind of corn that you grind to make cornmeal. It gets very tall and you leave it on the stalk until frost, when the stalk and the ears have turned brown. Then I harvest the ears, shuck them, shell out the corn, dry it in the oven on low, and grind it in an electric grinder, for cornmeal. It is very, very good.
Sometimes in August, though, I harvest a few of the "green" ears for roasting ears. This is an old-timey way to cook corn. It works for sweet corn varieties as well as for green field corn.
Carefully shuck the ears without pulling the shucks all the way off: you just pull them back enough to remove the silk from the ears. Then you fold the shucks back up over the ear and soak the ears in water for ten minutes.
Meanwhile you heat the oven to 375, or heat your grill, gas or otherwise. When the ears are finished soaking, you place them directly on the oven rack or grill, and roast them for 20-30 minutes. If you're using a grill, you should turn them from time to time.
When you remove them from the oven or grill, let them cool for a few minutes and then pull back the shucks. Again, don't pull them off: the shucks make a great handle for holding the corn while you put butter and salt on it and eat it!
The variety shown here is Tennessee Red Cob, from Southern Exposure Seed Exchange. The cob isn't red yet, but it will be at the real harvest time, in October.