Chocolate Potato Cake

Chocolate potato cake is the quintessential chocolate cake: rich, super chocolaty and very moist. A simple milky icing scented with brown sugar complements the cake’s deep chocolate flavor. Serve the layer cake at a birthday party or take it to a potluck—it’s so moist and dense that it won’t dry out or sag, even if you make it a few hours (or a day) ahead of time.

As unusual as it may sound, chocolate mashed potato cake is a classic vintage dessert. The recipe originated in Ireland in the early 1900s. Practical-minded bakers stirred budget-friendly mashed potatoes into cake batter instead of butter. The technique spread to the U.S. during the Great Depression, when ingredients like butter and flour were scarce. The potatoes don’t alter the flavor of the cake, but they add lots of moisture and richness.

This cake is a great way to use leftover mashed potatoes. But avoid adding milk and butter to the mashed potatoes, as this can affect the texture and lift of the cake.

Chocolate Potato Cake Ingredients

• Butter: Soften the butter before whipping it with the sugar; the softer butter is easier to beat and will take in more air than cold, hard butter. (More air means fluffier cake.)
• Sugar: Use plain white granulated sugar in this recipe.
• Eggs: Always bring eggs to room temperature before baking; they’ll incorporate better into the batter.
• Cold mashed potatoes: If you’re making fresh mashed potatoes for the recipe, use Russet potatoes, Yukon Golds or another starchy type of potatoes.
• Vanilla extract: Even though the cake is chocolate-flavored, we add vanilla, which lends a rounded, aromatic flavor. Use a good-quality brand of extract for the best flavor.
• All-purpose flour: Use plain all-purpose flour for this cake recipe.
• Baking cocoa: Look for a high-quality cocoa powder with a rich, not bitter, chocolate flavor.
• Baking soda: Baking soda helps leaven, or raise, the cake, ensuring a light crumb.
• 2% milk: A dash of milk adds moisture to the cake. If you prefer, use skim, whole or even nondairy milk—just don’t use any milk with added sugar or flavorings.
• Walnuts or pecans: Chopped nuts add a delightful crunch to the tender, moist cake.
• Caramel icing: Butter, brown sugar, evaporated milk, confectioners’ sugar and vanilla extract make the perfect icing for this chocolate cake. When measuring the brown sugar, pack it tightly into the measuring cup.

Directions

Step 1: Cream the butter and sugar

In a large bowl or stand mixer, cream the butter and sugar until light and fluffy, five to seven minutes.

Editor’s Tip: Don’t rush creaming butter and sugar. It helps aerate the batter, ensuring that the cake isn’t too dense.

Step 2: Add the eggs

Add the eggs, one at a time, beating well after each addition.

Editor’s Tip: The mixture may look curdled after the eggs go in, especially if any ingredient was cold. It will normalize as the remaining ingredients are added.

Step 3: Finish the wet ingredients

Reduce the beater speed, and add the mashed potatoes and vanilla extract.

Step 4: Add the dry ingredients and milk

In a separate bowl, whisk together the flour, cocoa and baking soda. Gradually beat the dry ingredients into the creamed mixture, alternating between the flour and milk, beating well after each addition. With a large spoon or spatula, gently stir in the nuts.

Editor’s Tip: Alternating between milk and flour helps the ingredients distribute evenly with less mixing. Overbeating the batter can activate the gluten and make it a bit tough.

Step 5: Bake the cakes

Pour the batter into two greased and floured 9-inch round baking pans. Bake at 350°F until a toothpick inserted in the center comes out clean, 25 to 30 minutes. Cool for 10 minutes in the pans before removing to wire racks to cool completely.

Step 6: Make the icing

In a saucepan over low heat, cook the butter and brown sugar until the butter melts and the mixture is smooth. Stir in the evaporated milk, then bring the mixture to a boil, stirring constantly. Remove it from the heat and let it cool to room temperature. Whisk in the confectioners’ sugar and vanilla, and stir until smooth.

Step 7: Ice the layer cake

Place one layer of the cake on a flat plate. Spread a layer of icing over the top. Place the second layer on top. Spread icing across the top. If desired, scatter extra pecans over the top.

Editor’s Tip: This recipe calls for adding icing to just the tops, leaving the sides of the cake open. If you prefer, you can ice the sides of the cake, too, creating a more formal-looking cake. Double the icing recipe if you want to cover the entire cake.

Chocolate Potato Cake Variations

• Lean into the chocolate: For a decadent chocolate dessert, try dark chocolate ganache or chocolate buttercream instead of caramel icing.
• Play with toppings: Shredded coconut, berries, candies or chocolate chips would be tasty scattered over the top.
• Go nutty: Slather the cake with a nutty frosting, such as coconut pecan or fluffy peanut butter frosting.

How to Store Chocolate Potato Cake

You can store potato and chocolate cake at room temperature or in the refrigerator. Either way, carefully wrap the cake in storage wrap or cover it with a cake dome. Keeping the air away will help preserve moisture.

How long does chocolate potato cake last?

At room temperature, chocolate mashed potato cake lasts for up to three days. The extra-moist cake keeps well but may begin to dry out slightly at the end of that time. In the refrigerator, the cake keeps well for up to five days. The frosting may harden as it chills; take the cake out of the fridge 30 minutes before serving to restore a tender texture.

Can you freeze chocolate potato cake?

Yes, you can freeze chocolate potato cake. After baking the cake layers, let them cool completely. Do not ice the cake. Wrap each layer tightly in storage wrap and foil, then freeze them for up to three months. Defrost the cakes in the refrigerator overnight before proceeding with the icing.

Chocolate Potato Cake Tips

Can you make chocolate potato cake in a different pan?

Yes, this cake bakes beautifully in other baking pans. You can bake the entire batch in a 9×13-inch pan for a big dessert perfect for taking to a potluck or picnic. (Just slather the icing right over the top!) The larger cake will take a bit longer to bake, so add five extra minutes to the baking time and check it every few minutes.

Likewise, the batter can be baked in a Bundt pan. Make sure to grease and flour the Bundt pan well so the cake won’t stick. Plan for the baking time to increase considerably in the deeper pan: Add 10 minutes and test it from there.

How should you make mashed potatoes for chocolate potato cake?

You can use your favorite mashed potato recipe—just use plain water instead of milk and skip the butter. If you made mashed potatoes with salt, that’s OK; the sweetness of the cake ingredients will balance the savory flavor.

Can you use instant mashed potatoes for chocolate potato cake?

Yes, you can use instant mashed potatoes for potato and chocolate cake—and it’s a good choice if pressed for time. Just follow the instructions on the package, but don’t add butter or milk to the instant potatoes.