I got both cup cakes and cake for my son's first birthday party too.
Let the baby take picture with both. The little cup cake is for him to play
and eat on their own (instead of waste the whole cake) was one of my reason
for preparing it. Another reason is like what 嘟嘟妈 said it looks pretty
and cute on the tower, and you could make it to match the theme of the party
. The big cake is for all the guest at the party of course that can include
your little one too ^^ Have fun!