Chocolate Sheet Cake

May 1, 2016

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This addictive Chocolate Sheet Cake is simply everything. The secret is in the double cocoa (yes, double!), whipped chocolate cream topping, and fresh strawberries. This is the best chocolate cake!

Chocolate Sheet Cake on Plate with Strawberries and mint garnish

Homemade Chocolate Sheet Cake

Life needs chocolate, period. Would I survive without chocolate? Maybe.

Would I be an enjoyable person without chocolate in my life? No. Does that make me an emotional eater? Probably, but I’m cool with that.

Really though, I love love love chocolate, and I also love love love chocolate cake! It is, after all, two of the absolute best foods combined into one so of course that makes it one of the most epic things in the world of food, right?

I think it’s safe to say this chocolate sheet cake recipe will have everyone swooning!

Why is this homemade chocolate cake any different from all the other sheet cake recipes out there? Because I’ve always doubled the cocoa from that in the classic chocolate sheet cake recipe and it makes it 1,000 times better!

I mean, 1/4 cup cocoa most definitely could not be considered enough for a whole cake!

I also chose to finish this one off with some chocolate whipped cream for extra decadence (it tastes like chocolate mousse), but it’s optional so if you want to cut back on ingredients feel free to leave it off.

Then of course I like to add some fresh strawberries, because strawberries and chocolate just go together, plus they add that gorgeous red color.

Creamy chocolate topping poured onto Chocolate Sheet Cake

Chocolate Sheet Cake Ingredients

For the chocolate cake itself, you’ll need:

  • All-purpose flour
  • Granulated sugar
  • Baking soda
  • Salt
  • Unsalted butter
  • Unsweetened cocoa powder
  • Hot water
  • Buttermilk
  • Eggs
  • Vanilla extract

For the homemade chocolate icing, you’ll need:

  • Unsalted butter
  • Unsweetened cocoa powder
  • Salt
  • Milk
  • Vanilla extract
  • Powdered sugar

And the optional toppings include:

  • Brown sprinkles
  • Fresh strawberries
  • Chocolate whipped cream

Best chocolate cake cut into squares and topped with chocolate mousse and strawberries

How to Make Chocolate Sheet Cake

  • Butter an 18×13-inch baking sheet and dust with cocoa powder.
  • In a large bowl, whisk together flour, baking soda, sugar and salt.
  • In a separate bowl, melt the butter. Stir in the hot water and cocoa powder.
  • Pour flour mixture into the butter mixture and stir to combine.
  • Add the eggs, vanilla and buttermilk and stir.
  • Bake until the cake is set.

How to Make Chocolate Icing

  • Cook butter, milk, salt and cocoa powder in a saucepan until the butter is melted.
  • Whisk in vanilla and powdered sugar, then pour over chocolate sheet cake.
  • Let the chocolate icing set at room temperature before slicing the cake.

Chocolate Sheet Cake Squares with chocolate mousse and strawberries

Can I Use a Buttermilk Substitute?

If you don’t have buttermilk on hand, just measure out 1/2 cup milk, remove 1 1/2 tsp of it then replace that with 1 1/2 tsp white vinegar or lemon juice. Stir and let it rest 3 minutes before adding to the chocolate cake batter.

Can I Use Dutch Process Cocoa Powder?

Without having tried it myself, I can’t say for sure. I used regular unsweetened cocoa powder, so I recommend using that if possible. It makes this cake richer and more chocolatey!

Why Ice the Cake When It’s Still Warm?

Normally, I’d advise you to wait until your cake has cooled completely before icing it, but with this chocolate sheet cake you want to ice it while warm. The icing oozes into the cake a little bit and makes it super moist. Trust me, it’s best to add the chocolate icing to a warm cake!

Full pan of chocolate sheet cake topped with bright red strawberries

Tips for the Best Chocolate Sheet Cake

  • The water added to the chocolate cake batter should be very hot. Warm tap water won’t do, you’ll need to heat the water on the stove or in the microwave.
  • Begin making the homemade chocolate icing as soon as the sheet cake comes out of the oven.
  • Wait to pipe on the chocolate whipped cream until you’re ready to serve the cake.

Spatula serving homemade chocolate cake from sheet pan

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5 from 4 votes

Chocolate Sheet Cake

This is the best chocolate sheet cake I've ever had! It is made with double to cocoa of the traditional chocolate cheese cake, so it's perfectly rich, and it's deliciously moist and fluffy, and who can resist that chocolate icing? It tastes like fudge and it's just too good!
Servings: 25
Prep20 minutes
Cook25 minutes
Ready in: 45 minutes



Chocolate Icing

Optional Toppings

  • Brown sprinkles
  • 20 - 24 fresh small strawberries
  • Chocolate Whipped Cream (see notes)


Make the Cake

  • Preheat oven to 350 degrees F. Butter a rimmed 18 by 13-inch baking sheet (average size cookie sheet) and dust lightly with cocoa powder and tilt to evenly coat, set aside.
  • In a medium mixing bowl whisk together flour, sugar, baking soda and salt for 20 seconds, set aside.
  • Add butter to a large microwave safe mixing bowl. Heat in microwave until melted. Whisk in cocoa powder and water. 
  • Pour flour mixture into butter mixture and using an electric hand mixer, blend until well combined. Add in buttermilk, eggs and vanilla and mix on low speed for about 45 seconds. 
  • Pour mixture into prepared baking dish. Bake in preheated oven until toothpick inserted into center of the cake comes out clean, about 20 - 25 minutes. 
  • Remove from oven and set on a wire rack to cool, immediately begin to make icing (you want to ice the cake while it's still really warm so it stays really moist and sort of absorbs some of the icing).

Make the Chocolate Icing

  • Add butter, cocoa powder, salt and milk to a medium saucepan. Cook over medium heat, stirring constantly, until butter has melted.
  • Remove from heat, whisk in vanilla and powdered sugar (if mixture is thick return to medium-low heat and warm, stirring constantly, until it has thinned. It should be a nice pourable consistency). 
  • Immediately pour icing over warm cake and spread into an even layer. If using sprinkles add immediately before icing begins to set. 
  • Allow icing to set at room temperature. Cut into squares, if using chocolate whipped cream add just before serving and a strawberry to each slice.


If you'd like to make the chocolate whipped cream: whip 3/4 cup + 2 Tbsp heavy cream in mixing bowl using an electric hand mixer until soft peaks form. Add in 2 1/2 Tbsp cocoa powder, 3 1/2 Tbsp granulated sugar and 1/2 tsp vanilla and whip to stiff peaks. Chill until ready to use.
Nutrition Facts
Chocolate Sheet Cake
Amount Per Serving
Calories 282 Calories from Fat 108
% Daily Value*
Fat 12g18%
Saturated Fat 7g44%
Cholesterol 42mg14%
Sodium 146mg6%
Potassium 78mg2%
Carbohydrates 43g14%
Fiber 1g4%
Sugar 33g37%
Protein 2g4%
Vitamin A 370IU7%
Calcium 21mg2%
Iron 1mg6%
* Percent Daily Values are based on a 2000 calorie diet.
Nutrition values are estimates only. See full disclaimer here.
Best chocolate cake in sheet pan topped with mousse and strawberries