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A slice of two layer chocolate cake on a white plate with a fork and a bite taken out

Double Chocolate Layer Cake (Chocolate Mayonnaise Cake)

  • Author: Leslie Kiszka
  • Prep Time: 15 minutes
  • Cook Time: 30 minutes
  • Total Time: 1 hour 15 minutes (includes cooling time)
  • Yield: 8-16 slices, depending on size 1x


This is my favorite chocolate cake recipe because it’s easy to make, ready in under an hour, and reminds me of the famous Portillo’s chocolate cake from Chicago! You might know this as “chocolate mayonnaise cake” – a moist chocolate cake, rich and chocolatey, covered in a thick layer of chocolate buttercream frosting, and layered for a decadent dessert. The perfect base for my homemade Portillo’s Chocolate Cake Shake.



Chocolate Cake

  • 1 box (15.25 ounces) Betty Crocker Super Moist Milk Chocolate cake mix
  • 3 large eggs, room temperature
  • 1 cup water
  • 1 cup mayonnaise

Chocolate Frosting

  • 10 ounces semisweet, milk, or dark chocolate chips
  • 1 1/2 cups unsalted butter, room temperature
  • 3 cups powdered sugar
  • 1 Tablespoon vanilla extract


Chocolate Cake

  1. Preheat oven to 350°F. Spray two round cake pans with non-stick spray and set aside.
  2. In a large bowl, combine cake mix, eggs, water and mayonnaise and beat with a hand or stand mixer on medium speed until well combined.
  3. Pour half of the batter into each of the prepared pans, and bake for 25-30 minutes or until a toothpick inserted into the center comes out with moist crumbs. 
  4. Let cool in pans for 5 minutes, then carefully remove from pans and transfer to wire racks (aff link) to cool completely.
  5. Once cooled, level off the top of one of the cakes (this will be your bottom layer). You can also level off both if you’d like the top to be flat as well. Set aside the pieces you’ve shaved off the tops and set aside.

Chocolate Frosting

  1. In a double broiler or in the microwave, melt chocolate until smooth and set aside to cool.
  2. In a large bowl, beat butter with a stand mixer or hand mixer (aff link) until smooth.
  3. Add powdered sugar and beat until well combined, starting on low speed and increasing as the powdered sugar incorporates.
  4. Add vanilla extract and melted chocolate, and beat until well combined and smooth.
  5. Place the leveled off cake layer on a platter and frost the top with 1/3 of the prepared frosting. Top with second cake layer and frost the top and sides of both layers with remaining frosting.


Storage: Store cake, covered, in a cool dry place for up to 5 days. Don’t put it in the fridge, though – it’ll dry out.

  • Category: Dessert
  • Method: Bake
  • Cuisine: American

Keywords: double chocolate layer cake, double chocolate cake, chocolate layer cake, portillo's chocolate cake, chocolate mayonnaise cake

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