So I'm trying to make a surprise cake for my son's birthday this weekend. I made a chocolate sheet cake and cut my shape out of it.  I put some batter in the bottom of the pan then stacked the shape along the loaf pan and covered with the remaining batter.  The problem I'm having is that the shapes are rising to the top of the cake when cooking.  Am I adding too much batter to the bottom of the pan?  Should I freeze the shapes a bit before stacking them?  Any help of tips would be greatly appreciated as I'm running out of time, ingredients and patients.

I don't exactly follow your post :(    Most likely you are adding too much batter if the cake is baking taller than you want.  I would at least cool the cake in the frig if not fz as you suggested.  It makes the cake easier to handle and less chance of it breaking. 

its one of those cakes that when you cut into it, there is a shape/cutout inside.  The cake is a yellow cake that when its cut into, reveals a batman symbol.  the problem is that the pre baked bat symbols are floating up to the top when baked inside the cake.

i haven't made one -- 

if i had this problem -- i would let that bottom layer of cake bake a bit first -- them implant the shaped sections into/onto that -- and add the rest of the batter --

i would try that -- i would use a small version in a small pan to test till i got it right and then did the full sized version with whatever i found that worked --

but hopefully others who have done this will chime in for you

Thanks...I had seen a few posts that prevailed that bottom just a bit to crust over then added their pieces...I'm going to try that as well as freezing the pieces slightly...I caved and bought cake mixes because I got tired of measuring lol.

cake mix is food -- it's ok --

i'm very interested in your results -- keep me posted ok?

i need to do one of these -- i get it going in my head and i'm too detailed -- gagh -- edit edit edit, k8 --

but please update -- thank you 

I've done this type of cake before and I found that you don't need much batter in the bottom, just a thin layer, and you could even push the design to the bottom of the batter so that it's touching the loaf pan and once it bakes, it will bake right in the middle. When I find the pictures of the ones I did, I'll post them. 

I started again this morning and finally had SUCCESS!  I froze the pieces for about 30 minutes while I prepared the second cake batter.  I poured a little bit in the bottom of the loaf pan and then baked it for about 7 minutes.  Then I put my pieces in and squished them in a lot more than I did on my previous attempts. Then covered with the remaining batter and baked fully.  I'm not sure if it helped that the cake consistencies were the same because they were both cake mixes but I'm just thankful that it finally worked as I needed 4 loaf pans all together and was running out of time.

Here are a couple of ideas for suspending the figure in the batter, although it is too late for the original poster, sorry!

the photos were upright when I hit send but posted sideways.  Anyone know why?