If you put the proper amount of sugar and spices in it, no one will know there are carrots in your carrot cake. Or zucchini in your zucchini bread. But you might be shocked if you found out that delicious chocolate cake you just ate was made with sauerkraut. The recipe for sauerkraut cake has been published many times, at least once under the title Don't Ask Cake. That one leaned on the habit of cooks serving the cake first and then daring the guests to identify the secret ingredient. Who came up with the idea of putting sauerkraut in chocolate cake? There's one origin story that reminds me of how we were served sauerkraut at least twice a week at my school cafeteria, but it may well be apocryphal. Bakers have long used vegetables, like carrots, to boost a cake's nutrition, and acids such as vinegar were used to make a cake rise before baking powder was invented. The history of sauerkraut itself is just as murky. We get both in an article at Atlas Obscura, as well as a recipe for sauerkraut cake, which they say is really tasty. In a good way.