Bumpy Cake Recipe

The iconic Michigan dessert: The Bumpy Cake! This fudgy, moist chocolate, buttercream and chocolate fudge frosting is a delicious copycat of the original.

In my research of the best cake recipes to share with you, I kept coming across something called “Bumpy Cake”. With the intriguing name, I had to check it out and came across this deliciously fudgy treat.

Thankfully this Michigan classic is also sold in Ohio at Meijer. I picked up a cake from the frozen food aisle, then recreated a version with my favorite chocolate cake. This is the result:

piece of chocolate bumpy cake on a plate

Why you’ll love this cake:

  • 100% homemade rich devil’s food cake
  • Classic chocolate and vanilla flavors
  • Buttercream bumps down the cake
  • Bakes in a traditional 9×13 cake pan
  • This bumpy cake features a delicious fudge icing

What is the origin of the bumpy cake?

Sanders Confectionary Company in Detroit, Michigan is famous for their chocolate candies, fudge toppings…and this bumpy cake! It was originally called “The Sanders Devil’s Food Buttercream Cake”.

As an article on sanderscandy.com describes, Fred Sanders created this cake when he ran out of buttercream to completely cover the top of a cake. This was a delicious accident! This cake is now shipped all over the world in many different flavors. It’s a fascinating story.

bite of bumpy cake on a plate

Key Ingredients:

  • Unsweetened Cocoa Powder: Use a traditional Hershey or Nestle cocoa powder, or use a mix of that and black cocoa powder for a gorgeously dark cake. In this cake, I used about 3 tablespoons of black cocoa powder and the rest was regular.
  • Buttermilk: Buttermilk will add flavor and keep the cake tender. Store bought buttermilk works best, but if you don’t have that, add a tablespoon of white vinegar to a measuring cup, then fill it the rest of the way with milk. Allow it to sit for 3-5 minutes, then stir and add to the recipe.
  • Coffee: Coffee enhances the flavor of a chocolate cake. It doesn’t make your cake taste like coffee. If you don’t want to use coffee you can use hot water. Or you can use water and add a teaspoon or two of espresso powder.
  • Dark Corn Syrup: Dark corn syrup adds color and a touch more flavor to the frosting recipe. If you’re in a pinch, you can use light corn syrup.

How to Make a Bumpy Cake

Make the cake.

This is a traditional, no fail chocolate cake recipe. Mix the wet ingredients and dry ingredients separately, then mix together and add the coffee last. This batter will be very runny, but will bake up beautifully.

When the cake is done, allow it to cool, then pop it into the freezer. It’s easiest to put on the buttercream and fudge frosting if the cake is partially frozen.

baked chocolate cake in a 9x13 pan

Make the buttercream.

Buttercream is always easiest to make with a stand mixer or electric mixer. This is so that the butter and sugars can cream together nicely.

You’ll notice we use both shortening and butter. This is to give it a more authentic flavor. The shortening also helps the buttercream have “staying” power when the fudge is poured over top because it has a higher melting point than butter.

Add the milk or heavy cream a tablespoon at a time until you get the perfect consistency.

white frosting lines piped on a chocolate cake

Pipe the buttercream.

Place the frosting in a decorating bag with a large round tip. (Wilton 1A or slightly smaller. This will depend on how tall you want your bumps.) If you’re in a pinch, use a zippered bag and cut the tip off. You might not end up with perfectly round stripes, but it will work if that’s all you have.

Pipe 4 frosting ribbons across the cake evenly. Place the cake back in the freezer while you make the fudge frosting.

Make the fudge frosting.

This is the hardest part of the recipe, but if you follow the instructions and use a candy thermometer while cooking, you shouldn’t run until any issues.

  • In a medium saucepan over medium low heat, combine the buttermilk, sugar, cocoa powder, salt and half of the butter. Bring the mixture to a boil and heat to the soft-ball stage (234-240 degrees Fahrenheit). We love our Thermaworks ThermaPen that instantly reads the temperature when making candy and fudge. Get one here. It’s amazing and perfect for grilling too!
  • Remove from heat and add the remaining butter cubes. Stir until melted.
  • Whisk in the powdered sugar and vanilla extract until well combined.

Take the cake out of the freezer and quickly pour the fudge frosting over the top of the. It will cool quickly once it hits the cold cake. Then place the cake back in the freezer to set for a few minutes.

chocolate cake with fudge frosting in a baking pan

How to Store the Cake:

Store the cake at room temperature in an airtight container. This cake also freezes well! Double wrap it and store for up to 8 weeks.

closeup of a piece of bumpy cake
closeup of a piece of bumpy cake

Bumpy Cake Recipe

4.67 from 9 votes
The iconic Michigan dessert: The Bumpy Cake! This fudgy, moist chocolate, buttercream and chocolate fudge frosting is a delicious copycat of the original.
Servings 15
Prep Time 20 minutes
Cook Time 40 minutes
Chill Time 45 minutes
Total Time 1 hour 45 minutes

Ingredients
 

For the cake:

  • 1 3/4 cups all-purpose flour 227.5 grams
  • 1 3/4 cups granulated sugar 350 grams
  • 3/4 cup unsweetened cocoa powder 100 grams
  • 1 teaspoon baking powder 5 grams
  • 2 teaspoons baking soda 12 grams
  • 1 teaspoon salt 6 grams
  • 1 cup buttermilk 244 grams
  • 1/2 cup canola oil or vegetable oil, 100 grams
  • 2 large eggs room temperature
  • 1 teaspoon vanilla 5 grams
  • 1 cup freshly brewed strong hot coffee 222 grams

For the buttercream:

  • 1/4 cup salted butter room temperature
  • ¼ cup vegetable shortening
  • 1 teaspoon vanilla
  • 2 cups powdered sugar
  • 4-6 tablespoons milk or heavy cream

For the fudge frosting:

  • ½ cup buttermilk
  • 1 cup granulated sugar
  • 1/3 cup dark corn syrup
  • cup cocoa powder we used a tablespoon of black cocoa powder and the rest regular cocoa powder for a great color
  • dash of salt
  • 1 cup salted butter cut into cubes and divided
  • 2 ½ cups powdered sugar
  • 2 teaspoons vanilla extract

Instructions
 

Make the cake:

  • Preheat oven to 350 degrees Fahrenheit. Grease a 9×13” baking pan with cooking spray. Line with parchment paper if you’d like.
  • For the cake, put flour, sugar, cocoa, baking powder, baking soda and salt in a bowl and whisk well.
  • In a stand mixer, mix the buttermilk, oil, eggs, vanilla together. Slowly add in the mix of dry ingredients while the mixer is on low. Add the coffee and make sure everything is combined. The batter will be very thin.
  • Pour the batter into the prepared pan and bake for about 30-35 minutes or until a toothpick inserted in the middle comes out clean.
  • Allow the cake to cool on a wire rack. After it is mostly cooled, place it in the freezer to so the topping is easier to apply. Try to let it freeze for at least 20 minutes.

Make the buttercream:

  • In a stand mixer using the whisk attachment, cream the butter, shortening and vanilla for 2-3 minutes until it is almost white in appearance.
  • Add the powdered sugar 1 cup at a time, while mixing on low speed. Cover the mixer with a dish towel, if needed, to prevent powdered sugar from blowing out of the bowl.
  • Add in the heavy cream a tablespoon at a time, and continue mixing on low. Add more cream as needed to get the desired consistency.
  • Place the frosting in a decorating bag with a large open circle tip. (Wilton 1A or slightly smaller. This will depend on how tall you want your bumps.)
  • Pipe 4 frosting ribbons across the cake evenly (they should be about 1-inch wide). Place the cake back in the freezer while you make the fudge frosting.

Make the fudge frosting:

  • In a medium saucepan over medium low heat, combine the buttermilk, sugar, corn syrup, cocoa powder, salt and half of the butter. Bring the mixture to a boil and heat to the soft-ball stage (234-240 degrees Fahrenheit).
  • Remove from heat and add the remaining butter cubes. Stir until melted.
  • Whisk in the powdered sugar and vanilla extract until well combined.
  • Remove the cake from the freezer and drizzle the fudge frosting over the cake evenly. If the fudge starts to harden, you can rewarm it to melt it again.
  • Put the cake in the freezer for 15 minutes to set.
  • Store in an airtight container. Any leftovers can be stored at room temperature for up to 3 days or in the refrigerator for up to 5 days.

Notes

The calories shown are based on the cake being cut into 15 pieces, with 1 serving being 1 slice of cake. Since different brands of ingredients have different nutritional information, the calories shown are just an estimate. **We are not dietitians and recommend you seek a nutritionist for exact nutritional information. The information in the nutrition box are calculated through a program and there is room for error. If you need an accurate count, I recommend running the ingredients through your favorite nutrition calculator.**

Nutrition

Calories: 644kcal | Carbohydrates: 95g | Protein: 5g | Fat: 30g | Saturated Fat: 13g | Trans Fat: 1g | Cholesterol: 74mg | Sodium: 487mg | Potassium: 200mg | Fiber: 2g | Sugar: 79g | Vitamin A: 607IU | Vitamin C: 1mg | Calcium: 63mg | Iron: 2mg
Course Dessert
Cuisine American
Calories 644
Keyword chocolate, copycat recipe, sheet cake

Recipe Variations:

  • Use your own favorite cake and buttercream recipes.
  • Replace the vanilla buttercream with a strawberry buttercream.
  • If you don’t want to make the fudge frosting, you could make a simple chocolate ganache with chocolate chips and heavy cream.
  • Add chocolate chips or nuts to decorate the top.
  • Use this technique with any flavor combination.

About Julie Clark

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5 stars
Thanks for the recipe, being a Michigander now in California I really enjoyed making a bumpy cake. Couple of things though, I noticed in the butter cream step I don’t believe you tell us to add the vanilla. And then in the fudge frosting step I didn’t see where it said to add the corn syrup. I figure it out, but you may want make that adjustment. Thanks again for a great recipe