Starchy and sugary stuff can go in a worm bin and makes good food for the critters. But it needs to be well moistened and aerated or it will get gross before it breaks down - definitely moldy (which doesn't matter in the long run) and possibly fermented (which is bad because it produces substances toxic to worms.) If you have a box full of something starchy to dispose of, I would mix it into other food stock thoroughly and only a little at a time, to avoid any gooey globs sticking together (a glob of pasty starchy stuff is likely to ferment).

Oh gosh - that typo was sooo funny !

I have found that my European Nightcrawlers will not touch any flour, corn meal, or ground oatmeal. I no longer feed them anything like that.

I believe in Marie Antoinette's famous words: Qu'ils mangent de la brioche! [let them eat cake!]

If I had that, I would mix it with the regular juice pulp I use as worm food as I did with other irregular stuff. My thinking, if I don't see it, it's gone to become compost.

If you open the cake mix and it smells or looks bad, then you could compost it, but even 6 months or more beyond the date, you could probably bake it up and eat it with no ill effects. If you can't see yourself eating it, then bake it, add whipped cream on top and give it to someone you don't like. And besides, the date is usually the 'best used by' date and not the date where Cinderella turns into a Pumpkin.