Okay, so I learned a valuable lesson doing this cake....the tiers MUST be at least 4" different in size to make this work visibly. I did my usual 6"/9"/12" combination, but as you can see....or rather you CAN'T see...the pink tops are concealed. The whole cake just looks chocolate. Grrrrrr!!!!
So, next time I'll know that the cake must be something like 6"/10"/14" for this "collar" effect to be visible.
Thanks to Cakebaker57 for the advice a few months ago regarding the collar!