This Retro Dessert From Michigan Takes the Cake

Recreate this chocolatey regional dessert at home.

Bumpy cake on a small plate with cross-section facing forward, and in the surroundings, another plate with a serving of cake, glasses of milk, and a stripped kitchen towel

Simply Recipes / Ciara Kehoe

When you're searching for a delicious dessert, nothing beats a classic chocolate cake. What makes a simple chocolate cake even better? How about stripes of creamy vanilla buttercream frosting and a gooey fudge coating, creating the ideal contrast of chocolate and vanilla flavors and textures? That, in a nutshell, is bumpy cake.

What Is Bumpy Cake?

The original bumpy cake was created in 1913 at Sanders Chocolate & Ice Cream Shoppe in Detroit, Michigan. It consists of a devil’s food cake with bumps of buttercream across the top. Pourable fudge finishes it off, making for a shiny coating. 

My recipe starts with a one-bowl chocolate cake—no mixer required. This helps keep the impressive cake as low-stress as possible and shrinks the number of dirty dishes.

The best part? Every time I cut into this cake and the striking bumps of frosting are revealed, I immediately impress anyone I’m serving it to. It’s an iconic dessert in Michigan and a favorite in my arsenal of dessert recipes.

Bumpy cake on a small plate with cross-section facing forward

Simply Recipes / Ciara Kehoe

No Piping Bag? No Problem

Using a piping bag with a round tip will help to create the large bumps of frosting across the top of the cake. If you don’t have one, grab a zip-top bag. Cut the tip off of one of the bottom corners and use it just like a piping bag.

Bumpy Cake Tips and Tricks

  • Use coffee to amp up the flavor: The recipe calls for an optional two tablespoons of brewed coffee. This will enhance the chocolate flavor without making the cake taste like coffee.
  • Don’t rush the chilling: Temperature plays a key role in making this cake. The chocolate cake needs to be cooled enough for the frosting to adhere to it. The frosting needs to be frozen and hardened so that it doesn’t melt when the warm fudge is poured on top.
  • Pouring the fudge: The fudge topping is pourable and can be a bit messy. You can either pour all of the fudge at once or work in two layers—pour half and let it set in the freezer for 10 minutes, and pour the remaining after.
Bumpy cake close-up (cut into individual slices with one slice facing camera to show cross-section cut)

Simply Recipes / Ciara Kehoe

Always Room for Chocolate Cake

Bumpy Cake

Prep Time 20 mins
Cook Time 30 mins
Chill Time 95 mins
Total Time 2 hrs 25 mins
Servings 12 servings
Yield 1 (9x13) cake

Ingredients

For the cake

  • 3/4 cup (150g) granulated sugar

  • 1/2 cup (100g) light brown sugar, packed

  • 1 1/2 cups (188g) all-purpose flour

  • 1 cup (84g) unsweetened natural cocoa powder

  • 1 1/2 teaspoons baking powder

  • 1 teaspoon baking soda

  • 1 teaspoon salt

  • 2 large eggs

  • 2/3 cup neutral oil, like canola

  • 1 cup buttermilk or whole milk

  • 1 teaspoon vanilla extract

  • 2 tablespoons brewed coffee, room temperature (optional)

For the frosting

  • 1/2 cup (117g) unsalted butter, softened

  • 5 cups (570g) powdered sugar, divided

  • 2 tablespoons milk

  • 1 teaspoon vanilla extract

  • 1/4 teaspoon salt

For the fudge topping

  • 3/4 cup (170g) unsalted butter, cubed

  • 1 cup (200g) granulated sugar

  • 1/2 cup (45g) unsweetened natural cocoa powder

  • 1/2 cup buttermilk or whole milk, room temperature

  • 4 tablespoons light or dark corn syrup

  • 1/4 teaspoon salt

  • 2 1/2 cups (284g) powdered sugar, sifted 

  • 1 teaspoon vanilla extract

Method

  1. Preheat the oven to 350°F.

    Grease a 9x13-inch cake pan with cooking spray. Line the bottom of the pan with parchment paper to ensure the cake doesn’t stick to the pan.

    Parchment paper-lined baking pan for bumpy cake recipe

    Simply Recipes / Ciara Kehoe

  2. Make the cake batter:

    In a mixing bowl or the bowl of a stand mixer, add the granulated sugar, brown sugar, flour, cocoa powder, baking powder, baking soda, and salt. Mix to combine until the mixture is free of any large clumps.

    Mix in the eggs and oil, then mix in the buttermilk and vanilla extract. Add the brewed coffee and mix until just combined and the batter is smooth and free of any streaks of the dry ingredients.

    Bumpy cake dry ingredients whisked together in a bowl

    Simply Recipes / Ciara Kehoe

    Bump cake batter in a bowl

    Simply Recipes / Ciara Kehoe

  3. Bake:

    Pour the cake batter into the prepared pan. Bake until a toothpick inserted into the center comes out clean, 22 to 25 minutes. Set it on a cooling rack to cool in the pan for 30 minutes, and then transfer it to the freezer to chill for 20 minutes.

    Baked bumpy cake in the parchment paper-lined baking pan

    Simply Recipes / Ciara Kehoe

  4. While the cake chills, make the frosting:

    In the bowl of a stand mixer, beat the butter on medium speed until pale and fluffy. Mix in 2 cups of powdered sugar, the milk, vanilla extract, and salt on medium-low speed. 

    Gradually mix in 2 1/2 cups of powdered sugar on low speed until the mixture comes together. Turn the speed up to medium and whip the frosting until very thick but fluffy, about 1 minute. You can add up to 1/2 cup of powdered sugar if the mixture isn’t thick enough.

    Frosting in a stand mixer bowl for Michigan bumpy cake recipe

    Simply Recipes / Ciara Kehoe

  5. Create the bumps:

    Once the cake is very cold, add the frosting to a piping bag or a zip-top plastic bag. Snip the corner making a hole an inch wide.

    Use the piping bag to pipe thick lines of frosting down the length of the cake, leaving about an inch between each line. Use any extra frosting to add additional bumps, or freeze the leftovers in an airtight container for future use. 

    Return the cake to the freezer for at least 30 minutes while you make the fudge topping.

    Frosting piped in long horizontal lines onto the cake for bumpy cake recipe

    Simply Recipes / Ciara Kehoe

    Frosting "bumps" added to bumpy cake

    Simply Recipes / Ciara Kehoe

  6. Make the fudge topping:

    In a saucepan on medium heat, melt the butter. Mix in the sugar, cocoa powder, buttermilk, corn syrup, and salt. Whisk until smooth and bring the mixture to a rolling boil. Cook for 3 minutes without stirring. 

    Remove from the heat and whisk in the sifted powdered sugar and vanilla extract until smooth. Let the topping cool slightly for 10 minutes so it’s not too hot for pouring.

    Butter melting in a sauce pan over a portable induction stove for bumpy cake recipe

    Simply Recipes / Ciara Kehoe

    Chocolate fudge boiling on the stove for bumpy cake recipe

    Simply Recipes / Ciara Kehoe

    Bumpy cake chocolate fudge whisked together in the sauce pan off the stove

    Simply Recipes / Ciara Kehoe

  7. Add the fudge topping and chill:

    Remove the frozen cake from the freezer, stir the fudge, and quickly pour it all over the top. Gently tilt the cake pan to move the fudge around to cover the whole top of the cake. Move quickly since the fudge topping will set up as it chills. You can use an offset spatula to help nudge it around. 

    Return the cake to the freezer to set for another 15 minutes before slicing and serving. Store leftovers in an airtight container in the fridge for up to 5 days.

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    Chocolate fudge added to the cake pan with the bumpy cake

    Simply Recipes / Ciara Kehoe

    Pan moved from side to side to spread chocolate fudge topping for bumpy cake recipe

    Simply Recipes / Ciara Kehoe

    Bumpy cake on a small plate with cross-section facing forward

    Simply Recipes / Ciara Kehoe

Nutrition Facts (per serving)
746 Calories
32g Fat
111g Carbs
6g Protein
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Nutrition Facts
Servings: 12
Amount per serving
Calories 746
% Daily Value*
Total Fat 32g 41%
Saturated Fat 12g 60%
Cholesterol 78mg 26%
Sodium 473mg 21%
Total Carbohydrate 111g 41%
Dietary Fiber 3g 9%
Total Sugars 92g
Protein 6g
Vitamin C 0mg 0%
Calcium 93mg 7%
Iron 5mg 28%
Potassium 95mg 2%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
Nutrition information is calculated using an ingredient database and should be considered an estimate. In cases where multiple ingredient alternatives are given, the first listed is calculated for nutrition. Garnishes and optional ingredients are not included.