Well, rushing to the computer and typing an urgent request to Ochef probably didn't help your cause either.

Remembering that heat gets to the center of the cornbread (cake, brownies, etc.) from the surface and edges, and that heat dissipates most quickly from the surface and edges once you take it out of the oven, the longer the cornbread is out of the oven, the more heat will have to be sent in again through the surface again to travel inwards. So it is likely you will overheat the outside before any meaningful heat reaches the center. It is surprising how quickly heat is lost once you take something out of the oven.

We think too much time has elapsed in 10 to 15 minutes for you to successfully pop your cornbread back in the oven. We might, however, cut off the outside (done) pieces of cornbread – even if they're smaller than usual – and put the underdone middle back in the oven if it has enough structure to hold its shape. We have also been known to take underdone pieces of cornbread, cut them in half horizontally, and fry the pieces on a buttered griddle or skillet. They still taste great, even if not served the way you intended.

We often cook bacon in the microwave oven and notice that if it is not completely done after the usual 4 minutes, and sits for a minute or so, it takes another full minute or two to finish it off, whereas if we get it cooking again within 20 or 30 seconds, it will only take a half minute or so to finish cooking. In our experience, if you don't get something done the first time, you have to jump through sometimes awkward hoops to get it done subsequently.