I made a cake for a friend's daughter's baby shower this past weekend. It was a 16" square cake with a winnie the pooh cake on top. I was so proud of this cake when I dropped it off because it turned out sooooo much better than I anticipated. I was even able to make the icing level (which is a huge issue for me) over that sinking that I noticed in the middle. Duh. Sinking=Raw. I got a message from her today telling me the cake was not fully cooked in the middle. 
I knew many people at the shower (I couldn't stick around for it...and I'm actually glad now) and I am sooooo incredibly embarassed.
Did you use a heating core? I use one with cakes 10" and up, along with bake even strips- it's really starting to make a difference in the few cakes I do! 
Well hopefully it wasn't a very big area that was uncooked- 16" is a pretty large cake- if it was just an area in the middle, there would be plenty of cake around it.
Most people I know carve a circle in the middle to use as a cutting guide anyways.
By the way, your cakes are awesome! I love the "Go, Dog, Go"!
I'm sure the Pooh cake was beautiful and the raw area couldn't have been that large.
I'm still new to this, but I know that even the bakeries have their bad days. I once ordered 3 different cakes from a very good bakery (before I got into this) and the first was good, the second was okay, and the last one was a complete disappointment- dry and bland.
I know it must be hard to deal with, but as someone mentioned, you learn something everyday.
I think your cakes prove you are talented! 
I'm sure they loved the design of the cake. Zenu brings up a good point that it was probably just the middle of the cake that wasn't cooked so that had to leave a lot of scrumptous cooked cake to eat. 
I personally don't like the heating core (too much patch work) so I use a #9 flower nail because it doesn't leave such a big hole in the cake. I too use the bake even strips. Also anything 10" or larger I cook at 325 degrees forever - ok maybe like 1.25 hours.
PS - don't be discouraged by this. It's better to know there is a problem so you don't repeat it!
Thanks so much. I knew my CC friends would get it. I was MORTIFIED and discouraged for a hot second. But, other folks on CC sharing their horror stories that I've read before made me remember that Stuff Happens...to all of us. I could think of worse things (like the Pooh falling over...which was my biggest fear). Thanks for your compliment and encouragement.
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