Searing removes seasoning from cast iron?
I had seasoned a cast iron grill pan, the kind with raised ridges on it, which I thought would be perfect for making a London Broil, as it could go from the stove top to the oven. But for some reason, the searing removed the seasoning, right in the center where the meat was in contact with the pan. The rest of the pan is still brown and shiny with the seasoning, but now there's this grey circle in the middle.
Was it the high heat that did it? Should I avoid using cast iron for searing? Maybe I will just have to transfer from a conventional pan to the cast iron when I put it in the oven.