I am doing a barbie doll cake, the wonder mold is too small so was thinking of using a large bowl. What would I use for heating core?

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GREAT question!

I made one in a Pampered Chef bowl before I knew anything about CC, but it was not edible...it was cute but only for show.

You can purchase heating cores separately. Check out some of the cake supply site.

Alternatively....any metal tube that is deep enough could be greased and floured and set down in the middle of the bowl of batter. It would have to be wide enough that it doesn't fall over. A flower nail probably won't work since a bowl would be deeper than the nail.

Do you need to use a core?
I had made a dog cake and cooked a part of the base of the dog in a large pyrex bowl and it came out with no problems.

I didn't use a heating core, I never had luck with them... just make sure you grease the bowl very well. If your unsure, maybe do a test run and see if it will work without one..Good luck!!

I would use the heating core for sure or the top and sides are going to burn before the middle finishes baking. Make sure to grease it well inside and out. You can fill the heating core about 1/3 way to have some extra cake to fill the plug hole if needed. You can find the heating cores sold separately at Hobby Lobby and other places.

I made a doll cake before learning of CC and I used a 1QT glass bowl filled half full. I did not use a heat core and had no problems! I just kept watching to make sure it did not burn since I was not sure of the time limit. Good luck and can't wait to see it!!