This Retro Chocolate Cake Is Easy and Super Fudgy, Thanks to a Secret Ingredient

I am a mayonnaise enthusiast. If something is made with the condiment—deviled eggs, macaroni salad, or tomato sandwiches—I know I will love it. That includes mayonnaise cake, a retro dessert with a moist, tender crumb and rich chocolate flavor. Made with flour, cocoa powder, sugar, and a few other pantry staples, this rich, fudgy cake is what I make when I find myself short on eggs or have a late-night chocolate craving.

Mayonnaise in a cake may sound odd, but the condiment—an emulsion of oil and water bound together by lecithin, a protein in egg yolks—is essentially made up of ingredients frequently used to prepare desserts. Cooks have been using mayonnaise to prepare chocolate cakes for nearly a century; mayonnaise cake was especially popular during World War Two, when ingredients like eggs, dairy, and sugar were rationed to support the war effort overseas, and more recently during the pandemic, when bakers once again found themselves facing bare supermarket shelves.

A Brief History of Chocolate Mayonnaise Cake

Many blogs credit Hellmann’s with having created the mayonnaise cake in 1937, but one of the earliest recipes I found for the dessert was published 10 years earlier, in a March 1927 edition of the Oakland Tribune. The recipe didn’t call for store-bought mayonnaise, but it did instruct cooks to make their own mayonnaise by whipping one egg in half a cup of vegetable oil before adding it to their cake batter. 

General Foods, the parent company of Hellmann’s and Best Foods, debuted its version in its 1937 dessert booklet Cakes and Cookies With Personality: Exciting New Recipes for Cakes, Cookies, and Frostings. The recipe came from Mrs. Paul Price, the wife of a General Foods sales executive. Though Hellmann’s wasn’t the first to make mayonnaise cake, they did popularize it. The company used the recipe in advertisements to promote their mayonnaise, touting the dessert as a "rich, moist cake” without the need for eggs or shortening. To this day, both Best Foods and Hellman’s share mayonnaise cake recipes on their websites.

Why Mayonnaise Cake Is the Secret Ingredient for Better Chocolate Cake

In my recipe below, full-fat mayonnaise adds moisture and richness. The acidity of natural cocoa powder and the vinegar in mayonnaise activate the baking soda, producing carbon dioxide that helps leaven the cake, while its salt enhances the other ingredients, adding complexity and depth of flavor. While the seasonings in a typical store-bought mayo (such as Hellmann's) will not affect the flavor of your cake, avoid using anything but plain mayonnaise, as using heavily seasoned mayonnaise can impact the flavor of your cake.

Mayonnaise's signature emulsion of oil and water produces an exceptionally fudgy cake with cling-to-your-fork levels of moisture: The lecithin helps the condiment stay emulsified, and that emulsification allows for a more even distribution of both fat and moisture within the cake batter. This helps the fat evenly coat the flour particles, limiting gluten development and producing a more tender cake. These features make it suitable for serving with nothing more than a dusting of powdered sugar, but it’s also a great canvas for frosting, ice cream, or hot fudge sauce.

Use Coffee Instead of Water for Bigger, Bolder Chocolate Flavor

Many vintage mayonnaise cake recipes call for water to help moisten the batter, but in my recipe below, I’ve replaced water with strong black coffee, which complements and intensifies the cake’s chocolate flavor. Hot tip: Brew your coffee at double the strength you’d make for drinking. Don’t worry if you aren’t a coffee lover, though—even with double-strength coffee, this cake doesn’t taste like coffee, just rich dark chocolate. And isn’t that what we all want from a chocolate cake?

For the Cake: Adjust oven rack to middle position and preheat oven to 350°F (175°C). Using nonstick spray, grease a 9- by 13-inch baking pan, then dust with all-purpose flour, shaking out excess.

Using a fine-mesh sieve, sift flour and cocoa powder into a large bowl. Add sugar, baking powder, baking soda, and salt and whisk to combine.

In another large mixing bowl, whisk coffee, mayonnaise, and vanilla extract until well combined and the mixture resembles foamy, milky coffee, about 20 seconds. Add dry ingredients and whisk until mixture just comes together and no visible dry spots remain, about 30 seconds. (Batter will be slightly lumpy; this is fine. Do not overmix.)

Using a flexible rubber spatula, scrape batter into prepared pan. Bake until a cake tester inserted in the center comes out clean and cake pulls away slight from sides of pan, 35 to 38 minutes. Transfer pan to a wire rack and allow cake to cool completely, 1 1/2 to 2 hours.

For the Frosting: In the bowl of a stand mixer fitted with the paddle attachment or in a bowl using an electric hand mixer, beat butter on medium-high speed until creamy, about 30 seconds. Add confectioners' sugar and cocoa powder, followed by milk and vanilla extract. Mix on low speed until fully incorporated, then increase speed to medium-high and beat until smooth and fluffy, about 3 minutes more. Using a small offset spatula or flexible rubber spatula, spread frosting over cooled cake. Slice and serve.

Special Equipment

9- by 13-inch baking pan, whisk, flexible rubber spatula, stand mixer or hand mixer

Notes

You can substitute regular mayo for vegan mayonnaise, but vegan versions rises more, and have a lighter, more open crumb. If possible, avoid using reduced fat mayonnaise, which produces a denser, chewier, and less flavorful cake.

Make-Ahead and Storage

The frosted cake can be loosely wrapped in plastic and refrigerated for up to 3 days—allow it to come to room temperature before eating.

Whole or sliced unfrosted cake can also be wrapped in a layer of plastic wrap, followed by a layer of foil, and frozen for up to 3 months. Thaw at room temperature.