and why try to do I always do stuff beyond my skill set??

Anyway, I want to make a "surprise inside" cake for my friend's shower.  A heart inside a chocolate cake.

(I'm doing the "cake-balls" way, not the iambaker way.) 

So I cut out my hearts, put them in (pointy side up), poured the chocolate batter in on top and baked.  

It sorta-worked.  The problem is, they all floated to the top of the pan, which means when I flipped the cake over, they all were "sunk" to the bottom of the cake.   It was actually very depressing looking.  

Sunken hearts at a baby-shower is probably not a great theme.

Anybody know what the deal is?  

The only things I can think of are:

• Chocolate cake batter is so much denser that the white cake floats
• Uncooked batter is so much denser that the baked cake floats
• The universe is conspiring against me.

Random info:

• I used boxed Betty Crocker batter
• It was a 10" round, which is what I plan on using.

Any thoughts or suggestions?

AI just made a polka dots inside cake, courtesy of this recipe and tutorial http://once-upon-a-pedestal.blogspot.com/2013/06/hidden-polka-dots-recipe-and-tutorial.html?m=1. There was a helpful list of reasons the balls might float, and how to prevent it. She also had tons of surprise inside cakes on her blog.

AThanks, Mermaid! I'll check it out right now!

emarcomd I saw the tutorial on polka dot inside cake.  Did everything they said and my balls started floating up as the cake cooked.   So I ventured to open the oven and started to push the balls back down into the half baked batter.  The balls stayed down at that point and the batter cooked all the way through.  I was very surprised once we cut it.  Look at the picture.

http://cakecentral.com/g/i/3215843/fondant-covered-and-decorations/u/908598/flat/1/

ARopalma, that looks great!

I did not read the link that mermaidcakery posted, but I did read a tutorial on heart cupcakes sometime recently. That person (don't recall which blog) par-baked the bottom half of the cupcakes, then put the hearts in the partially set-up batter and topped with more batter to finish baking. Able to picture that? The partially baked batter held the hearts upright and in place when the rest of the batter was added.

ac2teachk -- thanks for that -- that sounds like a good idea-- I'll check it out!