Chocolate Birthday Layer Cake

This easy, moist chocolate layer cake gets deep flavor from cocoa powder and espresso powder and moisture from vegetable oil.

Yvonne Ruperti

Updated August 03, 2023

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Overhead view of Birthday Cake — Serious Eats / Robby Lozano

Why It Works

Using vegetable oil in the batter makes the cake extremely moist.
Using both cocoa and espresso powder gives the cake a deep, chocolaty flavor. Sour cream adds a welcome lactic tang.
The frosting comes together quickly and without the need for chilling prior to assembling the cake.
Adding corn syrup to the frosting ensures a smooth result with no grittiness.

When the anticipation of decent presents and being another year older have long since evaporated like the memories of that first kiss in the back of the movie theater, I say thank god at least for birthday cake.

This cake is the perfect party cake. Dark, dewy, cocoa-espresso cake layers nest in heavy swathes of bittersweet chocolate frosting. Sitting tall and pretty, decked out in creamy swirls of chocolate, this cake dares you to resist. But you won't, and as you dig your fork into a slice, the velvety cake gently yields under the satiny icing.

But this cake is by no means fancy or elaborate. It's a basic cake that smacks of a simple, moist Betty Crocker cake—except this one's real. And I'm sure I don't have to tell you that this cake isn't just for birthdays. Every cook should have an easy-to-make, star chocolate cake to pull out of their recipe box at a moment's notice, and today I'm offering up my all-time favorite.

And did I say easy? You bet I did. This recipe is a lickety-split "dump and stir" method. Simply whisk the wet ingredients into the dry, and in the oven it goes.

Cocoa, espresso, and tangy sour cream flavor the cake. I also swear by vegetable oil in all my chocolate cakes—nothing makes a chocolate cake more moist. For the frosting, the best tasting, quickest frosting, hands down, is based on the very first recipe that I developed for Cook's Illustrated. Unlike chocolate ganache (which you have to chill until it sets), you can frost your cake as soon as you make it. And unlike most quick frostings (which are gritty from confectioners' sugar), swapping some of the sugar for corn syrup keeps it creamy. My chocolate cravings have gotten bigger lately, so this time around I tweaked the original by making it less sweet and more chocolaty. (For the best results use a high-quality bittersweet chocolate.)

To assemble, just spread a dollop of frosting in between the two cakes and sandwich them together. If you own a cake wheel and a spatula, you can spin this cake to professional perfection. Otherwise, just do what grandma always did—use the back of a soup spoon to whirl the shiny icing into soft swirly tufts. Sprinkle on the technicolor sprinkles or sugar confetti, load it up with candles, and celebrate another year to eat cake.

February 2012

This recipe was cross-tested in 2023 and updated with more accurate measurements to guarantee best results.

Recipe Details

Chocolate Birthday Layer Cake Recipe

Prep 10 mins

Cook 22 mins

Active 45 mins

Cooling Time 75 mins

Total 107 mins

Serves 12 to 14 servings

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Ingredients

For the Cake:

1 1/2 cups all-purpose flour (7 ounces; 195g)
1/2 cup cocoa powder (1 1/2 ounces; 42g), see notes
1 teaspoon baking soda
1/4 teaspoon Diamond Crystal kosher salt; for table salt, use half as much by volume
1 1/4 cups granulated sugar (8 3/4 ounces; 250g)
1 1/4 cups sour cream (10 ounces; 287g)
2/3 cup (160ml) vegetable oil
2 large eggs
1 teaspoon vanilla extract
1 teaspoon instant espresso powder

For the Frosting:

20 tablespoons unsalted butter, softened (10 ounces; 280g), see notes
1 cup confectioners' sugar (4 1/4 ounces;120g)
3/4 cup plus 1 tablespoon cocoa powder (2 1/2 ounces;74g)
Pinch kosher salt; for table salt, use half as much by volume
2/3 cup (160ml) light corn syrup
1 teaspoon vanilla extract
10 ounces (280g) bittersweet chocolate, melted and cooled

Directions

For the Cake: Adjust oven rack to middle position and preheat oven to 350°F (175°C). Line bottoms of two 9-inch cake pans with parchment paper and lightly coat the inside with nonstick cooking spray.
Serious Eats / Robby Lozano
In a large bowl, sift flour, cocoa, baking soda, and salt, and whisk to combine; set aside. In a medium bowl, whisk sugar, sour cream, oil, eggs, vanilla, and espresso powder until smooth.
Serious Eats / Robby Lozano
Whisk wet ingredients into dry ingredients until smooth. Divide batter evenly between prepared pans and smooth cake tops with rubber spatula. Bake until cake is just firm and a toothpick inserted into center comes out with just a few moist crumbs attached, 22 to 25 minutes.
Serious Eats / Robby Lozano
Let cakes cool in pans for 15 minutes. Remove cakes from pans, discard parchment, and let cool completely on wire rack, about 1 hour.
Serious Eats / Robby Lozano
For the Frosting: Meanwhile, in a food processor, process butter, confectioners' sugar, cocoa, and salt until combined and smooth, about 30 seconds, scraping down sides of bowl as necessary. Add corn syrup and vanilla and process until smooth, about 30 seconds, scraping down sides of bowl as necessary. Add chocolate and process until smooth and creamy, about 30 seconds. (See notes.)
Serious Eats / Robby Lozano
To Assemble the Cake: Place one cake, top side up, on a serving platter or cake pedestal. Using offset spatula, spread about 1 cup frosting over top of cake layer. Center second cake, bottom side up, on top, and press lightly to adhere. Spread remaining frosting evenly over top and sides of assembled cake. To decorate, use the back of a soup spoon to make decorative swirls on the cake or decorate as desired. Serve.
Serious Eats / Robby Lozano

Special Equipment

Two 9-inch cake pans, parchment paper, food processor

Notes

Be sure to use natural cocoa; do not use Dutch-processed cocoa powder as it may affect the leavening of the cake.

8-inch cake pans can be substituted for 9-inch cake pans. If using 8-inch cake pans, increase baking time to 25 to 30 minutes in Step 3. In Step 6, frost top of bottom cake layer with 3/4 cup frosting.

Do not over-soften butter or the frosting will be too loose. The butter should yield lightly to the touch (about 60ºF or 16ºC).

If the chocolate is too warm, the frosting may be too loose. If the finished frosting is too soft, briefly refrigerate until it firms up to a spreadable consistency.

Make-Ahead and Storage

The baked, cooled cakes can be wrapped in plastic wrap and frozen for up to 1 month. Thaw at room temperature before frosting and stacking.

The frosting comes together quickly, so we recommend making it right before assembling the cake.

The assembled cake can be covered and stored at room temperature for up to 2 days or refrigerated for up to 4 days. Bring to room temperature before serving.

Nutrition Facts (per serving)
646	Calories
43g	Fat
60g	Carbs
7g	Protein

Nutrition Facts
Servings: 12 to 14
Amount per serving
Calories	646
% Daily Value*
Total Fat 43g	55%
Saturated Fat 20g	99%
Cholesterol 83mg	28%
Sodium 172mg	7%
Total Carbohydrate 60g	22%
Dietary Fiber 5g	19%
Total Sugars 39g
Protein 7g
Vitamin C 0mg	1%
Calcium 55mg	4%
Iron 7mg	39%
Potassium 225mg	5%
*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.)