AI am making an 18 inch cake in July for a cousin but its the biggest cake I have ever made so I have some questions. Do you find that because the layers are heavy that you should use a filling that's a bit thicker like buttercream vs fruit fillings? I am cooking it in 2 half pans do I need a heating core or would a flower nail be sufficient? It's going to be In July in Washington so hottest weather would be is 80 and the chances of that aren't extremely high but she I make my buttercream thicker or use crisco instead of butter I am so worried about melting :/ Would you recommend a SMBC, IMBC, or just plain ol buttercream? This is my first cake sold to someone(however they are only paying for supplies) Any suggestions or help would be greatly appreciated!

i probably would not use a nail because although it's 18 inches long the other part of the pan is only 9" wide so i think it will bake ok--as far as which type of icing, you can use anything you want--i have never used a thicker icing for stacking cakes but a lot of people love to do this--i would have no hesitation to fill with whipped cream and fresh strawberries or any kind of fillings that i was already comfy with using--

i think you should use what you are already comfy with using or get practiced up on a new one and go for it--

i'm sure you know that you want to use a bottom board that is absolutely inflexible like nice thick foam core--and i'd have it at least 22 inches big for two inches all the way around--

best baking to you

AThank you!