For this roasted corn recipe I gave a range of 25-35 minutes. Some people like to blacken their corn slightly (by some people I mean me), but others don’t! Depending on your oven and the size of the cob after 25 minutes (with your oven at 350 F) the corn should be cooked through, but you can always leave it in for a bit longer or take it out early depending on how it looks.