Heating Core For 11'' Or Larger Cakes
Decorating By SgtGoodie Updated 30 Jun 2007 , 2:12pm by luv2cake
Here is a link to what one looks like...
http://www.qualitymatters.com/Wilton-Heating-Core-Decorator-Preferred-p/qm417-6100.htm
It helps conduct the heat into the middle of your cake so that it will cook evenly.
What a lot of us here do is we take a flower nail or two and invert them in the pan before pouring in the batter. This does the same thing as the heating core, but it doesn't leave a big hole in your cake. It is so much easier to use the flower nails.
HTH
Ditto what luv2 said. Just be sure to grease and flour the nail before you put it in the pan. 
Thanks luv2cake! I figured it was something like that. I've never used one before. Maybe my larger cakes were a little dry at the edges from being over baked while waiting for the center to finish. I never noticed, but it makes sense though. Thanks for the flower nail trick! I'm going to try that. 
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