I Always Add a Few Tablespoons of THIS to My Chocolate Cake Batter

When I was growing up I had this fascination with the chocolate cake I had seen in the movie Matilda. It looked decadent, chocolaty, and, most importantly, moist. It’s very common to come across chocolate cakes that are lacking in the moisture department, but did you know the key to the most moist chocolate cake could be inside your pantry right this moment? 

Forget eggs, butter, or even buttermilk — the answer is actually one you wouldn’t expect: mayo. To be honest, I got this trick from a family friend, so I can’t take all the credit. They were raving about an old family recipe for chocolate cake that they unfortunately no longer had. The one thing they could vividly recall was that the recipe had mayonnaise in it. I thought it was interesting, and wondered how that got in there. After a few hours researching (I love getting myself into baking rabbit holes), I found that it was a fairly common thing to do back in the 1940s. During that time, everyday household ingredients were being rationed during World War II, so it was very common to use mayo as a substitute for eggs, oil, and sometimes sour cream in baked goods. Somewhere along the way the practice became less common, but I am here to shine a light on this little-known hack.

Soon after, I pulled out my favorite chocolate cake recipe (which I happened to get from a bakery where I used to work) and tested it for myself. Long story short, it has been my go-to chocolate cake hack for many years since then (eight years, to be exact!).

Most chocolate cake recipes include a variety of fats, like butter, sometimes oil, and eggs. They are a staple in baking — not only for binding, but also for structure and leavening. If you look closely at the ingredients of mayonnaise, you will see that it commonly includes some sort of oil, egg, acid, and salt. 

To swap in mayo, I first tried removing the oil in the recipe entirely and replacing it with an equal amount of mayonnaise. The cake was moist, but still a little dense and it left me wanting more. While this technically “worked,” I still wanted the cake to be more moist — after all, I was aiming for the “Matilda chocolate cake” perfection.

After trying many versions of my favorite chocolate cake, I found that substituting the eggs with mayo worked best and created a ridiculously moist and delicious cake. I like to use a 1/4 cup of mayo to replace one large egg. It’s important to note that this works best if the cake recipe calls for oil, but if it doesn’t you can add an additional 1/4 cup mayo (I wouldn’t add more than a cup if the recipe doesn’t call for oil but has butter). The added fat in the mayonnaise creates the perfect level of moisture. And you may be wondering if the mayo leaves a tangy aftertaste or a flavor at all, but it really doesn’t. 

Keeping the extra oil in the recipe and simply replacing the eggs with mayonnaise makes a world of difference. Because it doesn’t work for all cakes, here are some tips to keep in mind.