I just found out that this surprise anniversary party will be in two weeks. I found an awesome sounding peanut butter filling recipe here that I have to use. And the Hershey cake recipe got good reviews here too, so I was thinking of using that for the cake.... still not sure if I should go with a white buttercream frosting or stick with all chocolate though.

But my big problem now is that I really don't know what shape/size of cake to make. There could be potentially 90 people there - although I'm sure not that many will make it, it's not going to be a small gathering. I did try looking at the charts that show servings, but I'm confused as to whether it means one layer or not - what should I do? What would you do? My largest pan is a 9x13 - should I go get some larger sheet cake pans? Should I just do bigger rounds and tier them? If I do do a rectangle, should I stack them 2 or 3 high?? I'm getting a bit anxious to figure this out - if I don't start finding time to play with this I'm going to be in big trouble - two weeks is going to fly by!

Are you wanting sheet cakes? How are you going to decorate it?

Well... I'd love to try tiers, but I've never done them and maybe this isn't the time since I don't actually have much time to play with this -- so maybe I should do a sheet cake(s) (keep in mind that I've never made anything larger than a 9x13 single layer!)
As for decorating, I was going to just smooth a buttercream and do something on the edges and use tons of royal icing flowers.

Even if someone could point me to somewhere on here that could help - I'd really appreciate it! A sheet cake seems more practical at this point, but even at that I have no idea how to make a "big" one!!

Anyone? I'm trying not to panic - I don't want to regret offering to make this cake. I feel ok about the decorating, but this size/shape thing has me stuck!!

One more question to add - can you even
practically layer sheet cakes?

A 9x13 cake with 2 (2 inch) layers provides 45 portions. Thus, a 13x18 will give you 90 portions. If you're going to do a sheet, you could use your 9x13 pan, bake 4 (2 inch) layers and put them together to make a single 13x18 cake. If you choose that option I would set 2 (2 inch) layers side by side, then center the third layer over the joint. Then I would cut the final layer in half (yielding two 4.5x13 pieces) and place 1/2 to each side of the centered layer. This would interlock the layers so that you wouldn't run the risk of having them split at the join. Alternatively, you could just do two 11x13 cakes of two 2 inch layers each. This might be your best option since when you are pressed for time is no time to be experimenting with things you've not done before.

If you want a torted effect, you could always bake eight 1 inch layers using your 9x13 pans and stack them in interlocking layers. Much simpler than trying to torte a 9x13 when you're pressed for time. That is how I did the dock in this cakorama (cake diorama):

http://cakecentral.com/gallery/2050053

I used a jelly roll pan to bake 8 one inch layers of vanilla cake then stacked them with raspberry jam (sieved to remove the seeds) and vanilla pudding buttercream.

Thank you so much for that help! That idea of offsetting the layers is what I needed to hear - I imagined a "fault line" developing if I just layed the two sheet cakes together.

I LOVE your cakes! I looked at your pier and then checked your blog - Your style is exactly what I love. Someday I'll get there.

Again, thanks for taking the time to explain all this - the sizes/servings really helped too.

I had to make a half choc, half vanilla cake last year and put them side by side so I ended up with a 9 x 18" cake.
http://cakecentral.com/gallery/1836000
I torted them but had I to do it over again I would have made two separate layers each. I dealt with the 'fault line' by first filling the space between them with buttercream and letting it harden then frosted each side as best I could in a straight line, then covered with flowers as shown.
I did a two layer sheet cake (9 x 13) recently and I liked it much better. You can see the sides are higher and I think looks better.
http://cakecentral.com/gallery/2065855

Wow Carmijok, I love both of them! I appreciate seeing the pics w/the sizes - it really helps give me a good idea of what I need to do!