In the past, my heart-shaped cakes have tended to get bigger and bigger, resulting in things like a heart the size of a small dog and the infamous Thoracic Cavity Cake. This year I decided to buck the curve and make very small, individual-portion-sized heart-shaped cakes.
There were 18 people coming to Pumpkinfest, so I needed to make 18 little, cupcake-sized hearts. I also wanted them to bleed because what would be the point of making heart-shaped cupcakes that didn't bleed? I thought it would be a nice touch to have both red blood (arterial) and blue blood (venous), so I made a batch of fresh raspberry sauce and a batch of fresh blueberry sauce. Both of these sauces are very delicious and very easy to make. The only ingredients are berries, sugar, and lemon juice, mixed up in a blender and strained through a sieve to remove the seeds. The blueberry sauce was perhaps less blue than it might optimally have been, but I think we all know how hard it is to find appetizing blue food.
To contain the sauces, I made two gum paste cylinders per cupcake, for a total of 36. The idea was that one of them would be the aorta (full of red blood) and the other the superior vena cava (full of blue blood). Mounted vertically on the top of each cupcake, they would hold the fruit sauces until the cupcakes were cut into, at which point they would spill their gory contents over the plate.
For the cake itself, I started with cupcakes, which are relatively heart-shaped to begin with. I removed the paper from each one and set them in the middle of white paper plates, the better to emphasize the soon-to-be-spilt fruit sauces, and covered them with a thick later of chocolate buttercream frosting.
I didn't want to use fondant to cover and sculpt these hearts because I thought that the proportion of fondant to cake would be overpowering at cupcake scale (not that it probably makes that much difference anyway since most people peel the fondant off before they eat the cake.) For some reason, I also decided not to use buttercream frosting. I don't recall why I made that decision because in retrospect, buttercream would clearly have been the way to go. Instead, I decided to use white modeling chocolate. I didn't do a very good job of making the modeling chocolate, so it came out very hard and a little grainy. I used it anyway. I rolled out circles of the modeling chocolate to drape over the whole cupcake and then shaped it a bit with some gum paste sculpting tools. Then I used royal icing to pipe on detail veins and attach the cylinders sticking off the top.
Because I had used modeling chocolate I needed to color the hearts with powdered food coloring mixed into cocoa butter. Water-based colors don't stick to chocolate. To get the hearts nice and shiny, I then painted on a layer of red- or blue-tinted piping gel. Because the piping gel is water-based, it didn't spread smoothly, but rather beaded in rills and pockets, which I thought was actually kind of a nice effect.
Right before serving, I filled the tubes with my two fruit sauces.
Reactions were mixed. Adults more or less agreed that the cake was tasty, but that the modeling chocolate was too thick, hard, and grainy to eat. I really should have used buttercream. One little boy, who had been promised a cupcake adamantly refused to accept that these were, in fact, cupcakes in a slightly different configuration and had to be supplied with a normal-looking cupcake that we fortunately had in reserve. His little brother, on the other hand, took to the little hearts immediately, breaking off the aorta and jugular vein and gleefully drinking the contents like a proper little cannibal.