Last year my cousin's daughter had a Halloween party (she was 7) and I made cupcakes with black cats, ghosts and witches on them (made of candy, of course!).
The decorated cupcakes are actually pretty easy to make. The part of the recipe I would need is the icing and decorations. You just make the cupcakes (chocolate of course, darker is more Halloween-y) and decorate them.
I'm not much of a baker, but one year I did buy a carroot cake at my local baker, and frosted it myself using orange frosting, then I used yellow frosting to put a Jack O'Lantern face on it.