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Homemade Decadent Bumpy Cake

A rich, dark chocolate cake topped with frozen buttercream ridges and smothered in a warm poured fudge frosting. A Detroit classic.
Print Recipe
Prep Time 45 minutes
Cook Time 35 minutes
Freezing Time 1 hour 40 minutes
Total Time 3 hours
Servings: 15 slices
Course: Cake, Dessert
Cuisine: American, Midwestern
Calories: 580
Ingredients Equipment Method Notes

Ingredients
  

The Cake
  • 2 cups all-purpose flour
  • 2 cups granulated sugar
  • 0.75 cup cocoa powder unsweetened
  • 2 tsp baking soda
  • 1 tsp baking powder
  • 1 cup buttermilk room temperature
  • 1 cup hot coffee freshly brewed
  • 0.5 cup vegetable oil
  • 2 large eggs
The Bumps
  • 1 cup butter softened
  • 3 cups powdered sugar
  • 1 tsp vanilla extract
The Fudge Pour
  • 0.5 cup butter cubed
  • 0.5 cup cocoa powder
  • 0.33 cup buttermilk
  • 3.5 cups powdered sugar sifted

Equipment

  • 9x13 Baking Pan
  • Piping bag
  • Saucepan
  • Electric mixer

Method
 

  1. Preheat oven to 350°F. Whisk flour, sugar, cocoa, baking soda, powder, and salt in a bowl.
  2. Add buttermilk, oil, eggs, and vanilla. Mix well. Stir in hot coffee until batter is thin.
  3. Pour into greased 9x13 pan. Bake 30-35 mins. Cool completely, then freeze for 30 mins.
  4. Beat softened butter, powdered sugar, and vanilla for the bumps until stiff.
  5. Pipe 4-6 thick logs of frosting across the cold cake. Freeze for 1 hour until hard.
  6. Boil butter, cocoa, and buttermilk for the frosting. Remove from heat, whisk in powdered sugar.
  7. Pour warm fudge over the frozen cake and bumps. Refrigerate to set.

Notes

Freezing the cake before adding the warm fudge is non-negotiable. If the bumps aren't frozen, they will melt away.