This Old-Fashioned ‘Mystery Cake’ Has a Shocking Secret Ingredient (2024)

Isn’t it fun to serve a recipe that has a secret little twist? Whether it’s a chicken dinner crusted with Cheez-Its, Mountain Dew in apple dumplings, or brownies with a black bean base, you get to be in on the cooking secret while everybody else is left in ignorant eating bliss.

Well, one "mystery" dessert recipe is trending again for putting an unexpected twist on a common cake that, we guarantee, no one in your house will detect. The magic lies in a super retro—and resourceful—baking solution that dates back almost 100 years ago. And yet, despite a near century of cake-making, the secret ingredient is still as mystifying to all who eat it.

What Is Mystery Cake?

Whether you hear it called mystery cake or magic cake, they’re both one thing: tomato soup cake. Yep, you read that right.

Believe it or not, you can use the savory soup to bake a totally delicious, not-weird-at-all tomato soup cake. But, unless you witness the ingredient going into the batter with your own eyes, you might not believe it's in there at all.

As it turns out, tomato soup has the right balance of salt, tang, and sweet to create a moist, light, and tasty treat. The flavor is warm and comforting like a traditional spice cake, while the consistency is similar to banana bread. Plus, the color of the cake turns out a rich burnt orange, so topped with a cream cheese frosting, it could easily pass for a carrot cake or pumpkin cake.

The History of the Mystery

The history of this cake makes the canned soup addition even cooler. The recipe dates back to the late 1920s or early 1930s, according to the Campbell Soup Company. During the Great Depression and World War II, ingredients like eggs and milk grew scarce, so home cooks had to get resourceful with what they had. Canned tomato soup was an affordable and accessible ingredient at the time, making it a perfect substitute for pricey baking staples.

From there, it was passed down through generations and is now beloved as one of Grandma’s best vintage cakes. After all, when a recipe sticks around for this long, you know it has to be good.

“I remembered my grandmother making this when I was a kid, so I searched for a recipe and this is the one I used,” said user veganalex, “and it's perfect.”

Why We Love Mystery Cake

As you’ve probably guessed by now, tomato soup cake doesn’t taste anything like tomato soup (thank goodness). Instead, the spices dominate the flavor, resulting in a sweet, taste bud-warming treat.

The tomato soup, taking the place of the milk and eggs, adds moisture and acts as the key binding agent in the cake. Plus, the heavy acidity in the ingredient plays two roles: it reacts with baking soda to give the cake a light, fluffy texture and it gives the crumb a richer, more complex flavor.

Who knew tomato soup could satisfy a sweet tooth?

So, when you want a dessert that’s uniquely delicious (and will leave your crowd guessing) here’s an easy recipe to follow. But, a word to the wise—if you choose to reveal the tomato soup secret, do so after everyone has fallen in love with the flavor.

How to Make Tomato Soup Cake

This cake is ready in just three steps and 50 minutes. To make it, start by combining tomato soup and baking soda together in a bowl. This will help neutralize the acidic taste of the canned ingredient.

Next, beat together sugar, butter, egg, cinnamon, cloves, and salt in a large bowl until smooth. Mix in the tomato soup mixture, then stir in flour and raisins. Note: Some reviews suggest omitting the salt (or using unsalted butter) because of how much sodium is already in the canned soup, while others add chopped nuts for more texture.

Pour the cake into a greased baking dish (loaf pan, Bundt, or muffin tin, depending on your favorite style), then bake in a 325-degree F oven for 50 minutes to an hour, or until a toothpick comes out crumb-free.