The project took me five days, but dividing the work over several days made it much more manageable. There is no reason to rush a cake like this. Each stage becomes easier when the previous stage has had enough time to chill, dry, or set.

Inside my car was a rich chocolate cake layered with simple syrup, soft chocolate-hazelnut ganache, toasted-hazelnut Italian buttercream, and chopped toasted hazelnuts.