Easiest Buttermilk Marble Bundt Cake

buttermilk marble bundt cake with chocolate ganache with 3 slices cut into it.

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This is the Easiest Buttermilk Marble Bundt Cake! This cake is simple yet showstopping when you slice into it to see the rich chocolate swirled with the sweet vanilla. Best of all, you only need to make one batter, not two, and it is so easy even a beginner baker can do it. 


Units Scale
  • 226g (2 sticks) salted butter, melted and slightly cooled
  • 280g white granulated sugar
  • 3 large eggs- room temperature
  • 50g full fat sour cream- room temperature
  • 2 teaspoons pure vanilla extract
  • 300g all purpose flour
  • 2 teaspoons baking powder
  • 1/2 teaspoon baking soda
  • 1/2 teaspoon kosher salt
  • 240g buttermilk- room temperature

For The Chocolate Cake

  • 35g Dutch processed cocoa powder
  • 1/8 teaspoon espresso powder
  • 4 tablespoons HOT water


  1. Preheat the oven to 325°F, then butter and flour a 10 cup bundt pan well, making sure to get in all the cracks and crevices.
  2. In a large mixing bowl, use a wooden spoon to stir together the melted butter, sugar, eggs, sour cream, and vanilla extract. Mix until well combined.
  3. Next, to the wet ingredients, add in the flour, baking powder, baking soda, and salt. Gently mix until just combined and no traces of flour remain. *do not over mix*
  4. To the vanilla cake batter, slowly pour in the buttermilk, then mix until you have a smooth batter.
  5. In a separate medium sized mixing bowl, whisk together the cocoa powder and espresso powder with boiling water until a thick paste forms.
  6. Transfer about 2 cups of cake batter into the bowl with the cocoa powder mixture and gently mix until fully combined. (this is your chocolate batter!)
  7. To your well greased bundt pan, pour in about half of the vanilla cake batter. Pour the chocolate batter in a circle on top, then pour the remaining vanilla cake batter on top of that. Use a sharp knife or wooden skewer to gently swirl the chocolate and vanilla together.
  8. Place the marble bundt cake into the oven and bake for 45-50 minutes, or until a toothpick inserted into the center comes out clean.
  9. Carefully remove the cake from the oven and allow it to cool in the pan for 10 minutes before inverting onto a wire rack to finish cooling completely.
  10. Once cooled, finish with a chocolate ganache glaze, a dusting of powdered sugar, or serve plain and enjoy!


  • Use room temperature ingredients: This is really important! When everything is the same temperature, the batter comes together more smoothly and results in a taller cake.
  • Measure properly: I know a scale is inconvenient for some people, but it's the most accurate way to bake. You can grab one at Amazon or Target for less than $15! (plus it uses less dishes this way)
  • Don't over swirl: It may not look completely swirled in the pan, but that is OK. You don't want to over swirl the batter or else you lose that beautiful marble look and it just looks muddy.
  • Grease you pan WELL: If you don't grease the bundt pan well your cake will stick. I like to butter it and dust lightly with flour so that way the cake just slides right out.
  • Add a glaze: A little drip of chocolate ganache is the perfect way to finish off this stunning buttermilk marble bundt cake.