This one-bowl chocolate sheet cake with easy fudge frosting is for all of you chocolate lovers!

This one-bowl chocolate sheet cake with easy fudge frosting is for all of you chocolate lovers!

When I asked my four year-old what kind of cake he wanted for his birthday, he shouted “chocolate!” He is my chocolate-loving kid and I love him for that.

We planned to celebrate with extended family at a neighborhood park, so I wanted a cake that transported well and could feed a crowd. What better time to develop a chocolate sheet cake recipe, right?

Here’s what I came up with— a basic homemade one-bowl chocolate cake frosted with easy fudge buttercream icing. This cake is moist, tender and intensely chocolaty. It’s perfect for any occasion, whether you want a quick weeknight dessert to satisfy that chocolate craving or you’re planning a birthday party. It certainly got my birthday boy’s stamp of approval!

This one bowl chocolate cake recipe couldn't be easier!

One-Bowl Chocolate Cake

For this recipe I decided to stick with my tried and true chocolate sour cream cake as a starting point. There’s no point in reinventing the wheel, and it’s been my favorite chocolate cake for several years now. Except, the last few times I’ve baked it I wondered if I could simplify things a bit more by combining some steps and eliminating a few dishes.

And it totally works! This chocolate cake mixes up just like a box mix— once the dry ingredients are combined you add all of the wet ingredients at once and mix until smooth. I prefer to use my stand mixer, but a hand-held mixer and even a whisk and elbow grease will work too.

Homemade chocolate cake doesn’t get any easier than this!

Simple chocolate sheet cake can be baked in a 9x13 pan or half sheet pan.

One Chocolate Sheet Cake Recipe, 3 Options

The great thing about this chocolate sheet cake is you have a few options when it comes to the size of the cake and how you want it to look. You can keep it super simple and frost and serve the cake straight from the pan, or you can make it a little fancier with two layers and a little decoration (as shown in this post).

  • 9×13-inch cake with two layers— Bake the cake in any 9×13-inch pan. Let the cake cool, wrap in plastic, and chill in the fridge for several hours and up to 3 days. Slice chilled cake in half to create 2 layers. See my tutorial on how to cut a cake into even layers for tips on how to do this, it really is quite easy! Cover one cake layer with frosting, then top with second layer. Frost entire cake as desired. Up to 24 servings.
  • 9×13-inch cake with a single layer— Bake the cake in any 9×13-inch pan. Let the cake cool in the pan or remove it from the pan if you want to serve it on something else. Once the cake is cooled, frost as desired. Up to 24 servings.
  • Half sheet pan (13×18-inch) cake— Bake the cake in a 13×18 sheet pan. Let the cake cool in the pan, then frost. 36-54 servings.

Easy fudge buttercream frosting takes this chocolate sheet cake up a notch!

How to cut perfect cake slices

When I posted a teaser of this cake in my instagram stories a reader asked “How did you cut such clean cake slices?” Lucky for all of us, cutting perfect cake slices is super simple!

  1. After the cake is assembled and frosted, chill in the fridge for at least 30 minutes before serving. This gives the cake layers and frosting a chance to firm up and become one.
  2. Make a plan. Know how many servings you want and eyeball where the cuts should be to get that number. Don’t just start slicing haphazardly.
  3. Use a long thin non-serrated knife to gently cut cake the cake, pressing down all the way till you hit the plate or stand at the bottom. Pull the knife out from the bottom (don’t drag it back up to the top).
  4. (This is the most important step!) Wipe the knife clean after each and every cut. You can use a towel, paper towel, or run your knife under warm water and wipe dry. This leaves the frosting on the top clean and pretty with no stray cake crumbs.

No matter how you slice it, this chocolate sheet cake is something everyone will love. From one chocolate lover to another, you’re welcome!

This one-bowl chocolate sheet cake with easy fudge frosting is for all of you chocolate lovers!

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This one-bowl chocolate sheet cake with easy fudge frosting is for all of you chocolate lovers!

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This one-bowl chocolate sheet cake with easy fudge frosting is for all of you chocolate lovers!
4.75 from 12 reviews

Chocolate Sheet Cake

Servings: 24 slices
Prep Time: 30 minutes
Cook Time: 40 minutes
Total Time: 1 hour 10 minutes
This one-bowl chocolate sheet cake with easy fudge frosting is for all of you chocolate lovers!


Chocolate Cake

  • 2 ½ cup all-purpose flour (330 grams)
  • 1 cup unsweetened cocoa powder (110 grams)
  • 1 teaspoon salt
  • 2 ½ teaspoon baking soda
  • 2 cup granulated sugar (400 grams)
  • 3 large eggs
  • 1 cup vegetable oil (265 ml)
  • 1 ¼ cup sour cream (282 grams)
  • 1 ¼ cup hot coffee (300 ml)

Fudge Buttercream Frosting

  • 6 ounces unsweetened chocolate , chopped (170 grams)
  • 4 ½ cup powdered sugar (563 grams)
  • 1 ½ cup unsalted butter , softened to room temperature (3 sticks, 340 grams)
  • 6 tablespoons whole milk or half and half (90 ml)
  • 1 tablespoon vanilla extract


To make the chocolate cake

  • Preheat oven to 350°F. Line a 9x13-inch pan with parchment paper and grease generously with nonstick baking spray.
  • In a large bowl or in the bowl of a stand mixer, add flour, cocoa powder, salt, baking soda and sugar. Mix until combined.
  • Add eggs, vegetable oil, and sour cream. Mix on low until combined.
  • With the mixer running, slowly add coffee. Stop and scrape down bowl once or twice to make sure everything gets incorporated. Mix for a few more moments until batter is smooth, but do not over mix.
  • Pour batter into the prepared cake pan. Bake until edges of the cake pull away from the pan and a toothpick inserted into the center comes out clean with a few crumbs, 35-40 minutes.
  • Let cool in the pan for 10 minutes, then transfer to a wire rack to cool completely. If you'd like to serve the cake straight from the pan, you can let the cake cool in the pan.

To make the frosting

  • Add all ingredients to a food processor and run for about 20 seconds until frosting comes together. Scrape down the bowl and run until smooth.
  • Frost cooled cake as desired.



  • This cake can also be baked in a 13x18-inch half sheet pan. Reduce baking time to 25-30 minutes. 
  • To make this a two-layer cake, follow these instructions for how to cut a cake into even layers. 
  • This frosting recipe makes about 4 cups which is enough to frost both a single or double-layer 9x13-inch cake or a 13x18-inch cake with some left over for decorating. Store any leftover frosting in the fridge for 1 week.
Calories: 388kcal, Carbohydrates: 54g, Protein: 4g, Fat: 20g, Saturated Fat: 12g, Cholesterol: 58mg, Sodium: 235mg, Potassium: 166mg, Fiber: 3g, Sugar: 39g, Vitamin A: 465IU, Vitamin C: 1mg, Calcium: 38mg, Iron: 2mg
Cuisine: American
Course: Dessert
Author: Annalise Sandberg
Have you tried this recipe?I’d love to hear about it! Leave a rating and review below, or take a photo and tag it on Instagram @completelydelicious with #completelydelicious.