Chocolate Sheet Cake, sometimes called Texas Chocolate Sheet Cake or Texas Skip Cake… a whole lot of names for one cake recipe. It is a rich, moist, chocolatey cake topped with one of the best boiled chocolate frostings you have ever had!
Once the chocolate cake comes out of the oven you pour on the frosting and it forms a delicate crystallized layer over the top. Once you have had this frosting you will never forget it.
Now, if it is a low calorie cake, keto, or “diet” cake that you are looking for- turn back now… this is NOT the recipe for you! But, if you want one of the best chocolate cakes you have ever had, you are in the right place.
Boiled Chocolate Frosting
I know that boiled frosting seems counterintuitive, but it works like magic! This is an old fashioned recipe, and our grandmothers knew what they were doing!
By boiling the frosting you allow the sugar to crystalize when it is poured on the cake. You end up with an delicate crystalized layer of frosting on top, and under that layer is warm fudgy frosting!
Buttermilk or Sour Milk
My hand written recipe calls for “sour milk” which is basically the same thing as buttermilk when it comes to baking. Back when this recipe was written you wouldn’t dare buy an entire carton of buttermilk just to use 1/2 cup.
Instead you mix 1/2 cup milk with 2 tablespoons of white vinegar and let it sit a few minutes to create a “homemade” buttermilk.
You can use either buttermilk or sour milk, both work great!
How to Make Chocolate Sheet Cake & Boiled Frosting
Start by preheating the oven to 350 degrees. Grease and flour an 18x12x1 sheet pan.
If you are using the sour milk method combine 1/2 cup milk and 2 tablespoons white vinegar and set aside. You can skip this step if you are using buttermilk.
In a large bowl combine 2 cups flour, 2 cups white sugar, 1 tsp salt. Set aside.
In a saucepan over medium heat boil 2 sticks of butter, 1 cup water, and 3 tbsp cocoa powder. Remove from the heat and stir into the flour/sugar mixture.
Crack and lightly whisk 2 eggs into a seperate bowl. Temper them slightly by adding a little of the warm batter into the eggs. Once they are tempered stir them into the batter.
Add 1/2 cup buttermilk (or 1/2 cup sour milk if using that method), 1 tsp baking soda, 1 tsp vanilla. Stir to combine.
Pour into your prepared sheet pan. Bake for 18-22 minutes until cooked through.
Boiled Chocolate Frosting
While the cake bakes, make the chocolate frosting so it can be poured on as soon as the cake comes out of the oven!
In a saucepan over low heat mix together:
- 1 cup butter
- 3 tbsp cocoa powder
- 5 tbsp milk
- 1 tsp vanilla
Once that is melted together stir in the powdered sugar. Stir until it is well combined.
Assemble the cake
As soon as the cake comes out of the oven pour on the frosting. Spread it evenly and then let it sit for an hour or two to crystalize and cool.
Serve cut into squares. You can serve with whipped cream, ice cream, or just as is!
Storing Chocolate Cake with Boiled Chocolate Frosting
Cut the cake into squares and store at room temperature, covered, for up to a week. (but I doubt it will last that long!)
Variations on the Chocolate Sheet Cake Recipe
We like this chocolate sheet cake as is, however you can dress this cake up to match your own taste buds. Here are just a few ideas:
- Stir a 1/2 cup chopped pecans, peanuts, or walnuts into the frosting before pouring over the cake.
- Sift powdered sugar over the frosting after it is poured on the cake for extra flair.
- Add a little mint extract to the frosting and then top each square with an Andes Chocolate Mint.
- Crush 2 Heath Candy Bars and add it to the frosting for a sweet crunch.
Homemade Chocolate Sheet Cake Recipe with Boiled Chocolate Frosting
Homemade Chocolate Sheet Cake with Boiled Chocolate Frosting
Chocolate Sheet Cake
- 2 cups All Purpose Flour
- 2 cups Sugar
- 1 teaspoon Salt
- 1 cup Butter (salted or unsalted)
- 1 cup Water
- 3 Tablespoons (heaping) Cocoa
- 2 Eggs
- 1/2 cup buttermilk If you do not have buttermilk you can use sour milk = mix 1/2 cup milk with 2 Tablespoons white vinegar and let sit for 2-3 minutes.
- 1 teaspoon Baking Soda
- 1 teaspoon vanilla
- 1 cup Butter
- 3 Tablespoons Cocoa
- 5 Tablespoons Milk
- 1 teaspoon Vanilla
- 3 1/2 cups Powdered Sugar
- Preheat the oven to 350. Prepare a large sheet pan (18x12x1) by greasing and flouring.
- If you are using sour milk method- combine 1/2 cup milk with 2 tbsp white vinegar and set aside. If you are using buttermilk you can skip this step.
- In a large bowl combine flour, sugar and salt. Set aside.
- In a saucepan over medium high heat bring to a boil 1 cup butter, 1 cup water, and 3 Tablespoons cocoa. Remove from heat and stir into the flour/sugar mixture. Next add 2 slightly beaten eggs (you may want to temper your eggs slightly with a tablespoon of the warm batter ), 1/2 cup sour milk, 1 tsp baking soda, and 1 tsp vanilla. Stir to combine. Pour into prepared sheet pan.
- Bake for 18-22 minutes.
- While the cake is baking prepare your frosting so it can be poured on as soon as the cake comes out of the oven.
- In a saucepan over low heat mix together 1 cup butter, 3 tbsp cocoa powder, 5 tbsp milk, and 1 tsp vanilla. Stir until it is melted and then add the 3 1/2 cups powdered sugar. Stir until it is well combined.
- As soon as the cake comes out of the oven pour the frosting over the cake. Smooth with a offset spatula or knife. Let rest 1 hour for the frosting to set before serving.
- Store at room temp, covered, for up to a week.
Dessert & Cake Recipes
Here are a few other dessert and cake recipes to check out!
- Carrot Cake with Cream Cheese Icing
- Cherry Pie Bars
- Easy Apple Pie Bars
- Summer Berry Cobbler
- Raspberry Lemonade Icebox Cake
Originally posted Sept 17, 2017 Copy & Photos updated on Dec 31, 2019