Maybe a creme brulee where you only put sugar in a mockingjay pattern? Or something with a Mockingjay of meringue.
Another way to go (not as dramatic as your brulee+reveal idea) is to adapt the giant chocolate chip cookies that are made to serve as dessert for a whole dinner party.
To adapt -
* bake on a sheet pan, not in a skillet.
* shape a fairly stiff cookie dough to resemble the bird (sketch out first on parchment paper)
* replace the choc chip dough with a simpler one, like shortbread, to provide a clean background for paints
* finish with edible paints
* present in the dark with birthday candles
You could use a stencil of the Mockingjay for the sugar on top and then torch it.