Image: AP

This is a question faced anew every time you feel moved to celebrate a loved one with something besides a sensibly sized cupcake, because you never can quite remember what you did the last time and whether it worked. So let’s just hammer this out right now.

We’re not talking about ordering for a large party or even to bring to a dinner out; that requires a different equation based on number of attendees and other food options available and assumes that nobody will be planning on leftovers. This is specifically in reference to household birthday cakes, whether for roommates or nuclear families or communes or any arrangement that involves some number people who like birthday cake living together under one roof.

Here’s my theory: The perfect size birthday cake allows everyone living in the household to have two and a half to three and a half pieces of cake, or roughly three days of cake total. The last day of cake is stale, but the third day is really crucial, here, because there’s something both wistful and freeing about polishing off that last, past-its-prime piece. It’s a nice goodbye to the birthday festivities, bittersweet but appropriate.

For instance, the last two times I purchased a birthday cake, I acquired round cakes with two layers, a fat slab of icing in the middle. The first was something like 10 inches, and entirely too goddamn big, so much so that I brought giant smeary chunks of cake to the Jezebel offices in Tupperware two days in a row and I still threw away some of that monster. {Editor’s note: That cake was so delicious.] The second cake was 6 inches and totally perfect. Just enough cake to feel decadent but not so much that you feel haunted by the remains that glower at you from your kitchen counter. I suspect this is the optimal size for up to three adults; with four people you’ll probably need to bump up to 8 inches, although you’re really going to have to find a fifth person to take at least one slice. Invite a friend over!

Please share your own theory of optimal cake sizing. In fact, please consider this a forum for any and all birthday cake takes you’ve had marinating; for instance, my theory is that lard-y buttercream is a pox on cakes and that any birthday cake without sugary icing should throw itself directly into the trash.