Yay, it's done!
I borrowed the idea for this card from Hiroko at Canon's Creative Park.
Here are all the pieces, cut out. The bottom cake layer is 4" in diameter and the top one is 2.5".
Don't the pieces look like they're floating? Here I was shoving the flowers around on the plain paper model to see where I wanted them.
Cake sides glued into rings.
Marking the placement of the cake on the card, arranging the cut-out hearts, and a peek at the front.
Putting it all together.
The front of the card (sentiment not inked yet).
And the back. The heart covers the tab that pulls the side of the bottom cake.
Hours later...I don't think I'll ever make this one again!