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Chocolate Mashed Potato Cake

Chocolate Mashed Potato Cake recipe takes leftover mashed potatoes and turns them into a moist chocolate cake!

Prep Time
20 mins
Cook Time
20 mins
Total Time
55 mins
Servings: 20 servings
Calories: 265 kcal
Course: Dessert
Cuisine: American

Ingredients

Chocolate Mashed Potato Cake
  • 1 ¾ cups cake flour
  • 1 ½ teaspoons baking soda
  • 1/2 teaspoon salt
  • 1/2 cup butter at cool room temperature
  • 1 ½ cups granulated sugar
  • 2 large eggs at room temperature
  • 1 cup buttermilk at room temperature
  • 1 teaspoon vanilla extract
  • 4 ounces unsweetened baking chocolate melted and cooled slightly
  • 3/4 cup plain mashed potatoes warm
Chocolate Frosting
  • 12 tablespoons butter softened
  • 3 cups powdered sugar
  • 3 ounces unsweetened baking chocolate melted and cooled slightly
  • 3-4 tablespoons milk, half-and-half, or heavy cream

Instructions

To make the cake
    Cup of Yum
  1. Preheat oven to 350 F. Grease and flour a 9x13-inch baking dish. Set aside.
  2. In a medium bowl, whisk together flour, baking soda, and salt. Set aside.
  3. In a large bowl, beat butter and sugar together until combined. 
  4. Beat in eggs, buttermilk, and vanilla until well-combined.
  5. Add mashed potatoes and melted chocolate. Mix until incorporated. 
  6. Stir in flour mixture until just incorporated. 
  7. Pour batter into prepared baking pan, smoothing as needed.
  8. Bake for 35-50 minutes, or until a wooden toothpick inserted in the center comes out clean. 
  9. Let cake cool to room temperature before frosting.
To make the frosting
  1. Beat butter and powdered sugar together until well-combined.
  2. Mix in chocolate and milk until completely incorporated. 
  3. Spread over cooled cake. 

Notes

  • Cake flour: If you don't have cake flour, you can make a homemade substitute with this recipe. Also, to properly measure the flour, stir or sift it to break it up, lightly spoon it into the measuring cup, and level.
  • Butter: I use salted butter in this recipe. You can use unsalted if you prefer. "Cool room temperature" means that the butter is about 68F. The butter should dent when pressed, but the stick shouldn't lose its shape or be smooshy.
  • Buttermilk: You can use regular or low-fat buttermilk. If you don't have buttermilk, you can make a substitute with this recipe.
  • Mashed potatoes:  Instant or regular will work. If you don't have leftover mashed potatoes, I have a section above the recipe that describes how to make enough mashed potatoes for this cake.
  • Nutrition facts are estimates.

Nutrition Information

Serving 1serving Calories 265kcal (13%) Carbohydrates 36g (12%) Protein 3g (6%) Fat 13g (20%) Saturated Fat 8g (40%) Cholesterol 39mg (13%) Sodium 234mg (10%) Potassium 124mg (4%) Fiber 1g (4%) Sugar 24g (48%) Vitamin A 290IU (6%) Vitamin C 1.8mg (2%) Calcium 30mg (3%) Iron 1.6mg (9%)

Nutrition Facts

Serving: 20servings

Amount Per Serving

Calories 265

% Daily Value*

Serving 1serving
Calories 265kcal 13%
Carbohydrates 36g 12%
Protein 3g 6%
Fat 13g 20%
Saturated Fat 8g 40%
Cholesterol 39mg 13%
Sodium 234mg 10%
Potassium 124mg 3%
Fiber 1g 4%
Sugar 24g 48%
Vitamin A 290IU 6%
Vitamin C 1.8mg 2%
Calcium 30mg 3%
Iron 1.6mg 9%

* Percent Daily Values are based on a 2,000 calorie diet.