Marble Cake

A soft, fluffy, moist vanilla and chocolate marble cake
Course Breakfast
Cuisine American
Keyword cake, marble cake
Prep Time 25 minutes
Cook Time 35 minutes
Total Time 1 hour
Servings 12 slices
Calories 770kcal
Author Sam Merritt


  • 4 oz semisweet chocolate finely chopped
  • 1/2 cup unsalted butter softened (113g)
  • 1/2 cup canola oil (120ml)
  • 1 1/2 cup sugar (300g)
  • 4 large eggs room temperature
  • 2 teaspoons vanilla extract
  • 3 cups all-purpose flour (390g)
  • 1 Tablespoon baking powder
  • 1/2 teaspoon salt
  • 1 1/4 cup buttermilk room temperature (300ml)

Chocolate Buttercream Frosting

  • 1 cup semisweet chocolate chips (170g)
  • 1 cup unsalted butter softened to room temperature (226g)
  • 2 cups powdered sugar (320g)
  • 1/2 teaspoon vanilla extract
  • 1/2 teaspoon salt
  • 2 Tablespoons heavy cream


  • Preheat oven to 350F and generously grease and flour two 8" round cake pans.  Set aside.
  • Place chopped chocolate in a microwave-safe bowl and microwave for 30 seconds.  Stir well, and then return to microwave and heat in 15-second increments, stirring well in between, until chocolate is completely melted and smooth.  Set aside.
  • Using an electric or stand mixer, cream together butter, oil, and sugar until light and fluffy (about 30 seconds on high speed).
  • Add eggs, one at a time, beating well after each addition.  Pause as needed to scrape down sides and bottom of bowl.
  • Stir in vanilla extract.
  • In a separate, medium-sized bowl, whisk together flour, baking powder, and salt.  
  • Using a spatula and gently hand-mixing, alternate adding flour mixture and buttermilk, starting and ending with flour mixture and mixing until just combined after each addition.  Do not overmix!
  • Pour 1/3-1/2 of the batter into a separate bowl and add chocolate mixture.  Stir until completely combined and batter is evenly chocolate.
  • Alternate adding vanilla and chocolate batter to each pan, evenly distributing batter into each pan.  Use a knife to swirl for marbled appearance.
  • Bake on 350F (175C) for 30 minutes, or until toothpick inserted in center comes out mostly clean but with a few moist crumbs (do not over-bake or the cake will be dry, you want there to be a few crumbs).
  • Allow cake to cool for 15 minutes before carefully inverting onto cooling rack to cool completely before frosting.

Chocolate Buttercream Frosting

  • In a microwave-safe bowl, microwave chocolate chips at 15 second intervals, stirring between intervals, until chips are completely melted. Set aside and allow to cool slightly (about 10 minutes, stirring occasionally).
  • Cream room temperature butter with an electric mixer. Stir in slightly cooled chocolate and beat well.
  • Gradually add sugar, scraping down the sides and bottom of bowl occasionally.
  • Sprinkle in salt and vanilla extract, stir well.
  • Gradually add heavy cream, increase speed to high and beat for 1 minute.
  • Spread a thick layer of frosting over the top of one cake round and sprinkle with mini chocolate chips. Top with second cake round and evenly frost cake. Slice and serve.


Serving: 1slice | Calories: 770kcal | Carbohydrates: 84g | Protein: 8g | Fat: 46g | Saturated Fat: 22g | Cholesterol: 139mg | Sodium: 256mg | Potassium: 337mg | Fiber: 3g | Sugar: 55g | Vitamin A: 901IU | Calcium: 111mg | Iron: 3mg