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Homemade Chocolate Brownie Cake Recipe

This homemade Chocolate Brownie Cake recipe creates a delicious hybrid of chocolate brownies and a Texas sheet cake. The cake is topped with luscious chocolate icing made from scratch.

slices of chocolate brownie cake

Most brownie recipes only make an 8×8 or 9×9 batch. I came up with this Homemade Chocolate Brownie Cake in order to make a larger batch.

I combined some elements of a few recipes, tweaked them a little, and bam! These chocolate brownies are what some may call a Brownie Sheet Cake.

How To Make a Chocolate Brownie Cake

To make a 9×13 pan of chocolate brownie cake from scratch, you need the following ingredients:

Chocolate Syrup

  • ¼ cup unsweetened cocoa powder
  • ½ cup water
  • 1 cup sugar
  • 1 tsp vanilla
  • ¼ tsp salt

Brownie Cake Batter

  • 1½ cups all-purpose flour
  • 1 tsp baking powder
  • 1 tsp salt
  • 2 Tbsp espresso powder
  • 10 Tbsp butter
  • ¾ cup baking cocoa
  • ¼ cup vegetable oil
  • 2 cups sugar
  • 4 large eggs
  • 2 tsp vanilla extract
  • two-thirds cup chocolate chips
  • Chocolate Syrup

Chocolate Icing

  • 1¼ cups chocolate chips
  • 3 Tbsp corn syrup
  • 1 stick butter

Start off by making a simple chocolate syrup. Just sugar, cocoa, water, vanilla, and a little salt.

boiling chocolate

The reason to make the syrup first is because it has to come to a boil and then cool. It will thicken some during the cooling period.

Prepared Pan

While the syrup is cooling, start the other aspects of the brownies, like preparing a 9×13 pan. I like to line it with aluminum foil that has been sprayed with non-stick spray.

Next, gather the other ingredients together. (Above is flour, baking powder, salt, and espresso powder.)

It’s best to add eggs one at a time. I like to crack all of mine into a little glass bowl before adding them. You never know when you will run across a bad egg.

Now, microwave the butter until it is melted in a medium size glass bowl. Add cocoa and oil and whisk until smooth.

Transfer the cocoa mixture to a bowl of an electric mixer. Stir in the sugar and add eggs, one at a time, mixing well after each addition. Add vanilla.

Gradually add the flour mixture. Pour in chocolate syrup and chocolate chips.

Pour batter into prepared 13×9 pan and bake for 25-30 minutes or until done. Let cool before icing.

This is how it looks before the icing is added.

The icing is a simple chocolate glaze made with chocolate chips, butter, and a little corn syrup.

To make the icing, melt chocolate chips and butter together in a microwave-safe bowl in 30 second intervals on high, stirring well after each segment. (It took me a total of one minute + an additional 10 seconds.)

Add corn syrup and stir until smooth. Let sit for 5 minutes before pouring over brownies.

Brownie Sheet Cake
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4.6 from 42 votes

Chocolate Brownie Cake

Chocolate Brownie Cake – this dessert recipe is so good. It's a mix between a brownie and chocolate sheet cake. Yum!
Course Desserts
Cuisine American
Keyword brownie, cake, chocolate
Prep Time 15 minutes
Cook Time 40 minutes
Total Time 55 minutes
Servings 16 slices
Calories 492kcal
Author Lynda

Ingredients

Chocolate Syrup

  • ¼ cup unsweetened cocoa powder
  • ½ cup water
  • 1 cup sugar
  • 1 tsp vanilla
  • ¼ tsp salt

Brownie Batter

  • cups all-purpose flour
  • 1 tsp baking powder
  • 1 tsp salt
  • 2 Tbsp espresso powder
  • 10 Tbsp butter
  • ¾ cup baking cocoa
  • ¼ cup vegetable oil
  • 2 cups sugar
  • 4 large eggs
  • 2 tsp vanilla extract
  • two-thirds cup chocolate chips
  • Chocolate Syrup

Chocolate Icing

  • cups chocolate chips
  • 3 Tbsp corn syrup
  • 1 stick butter

Instructions

  • To make the syrup: in a medium or large saucepan, whisk the cocoa powder and sugar until well blended. Add water and whisk over medium-high until it starts to boil and becomes a little frothy. Continue boiling for approximately 3 minutes. Reduce heat and allow to simmer for 2 more minutes. Remove from the heat and add salt. Let cool.
  • Preheat oven to 350 degrees. Line bottom of 13×9 pan with aluminum foil and spray with non-stick cooking spray.
  • Combine flour, baking powder, salt, and espresso powder and set aside.
  • Microwave butter until melted in a medium size glass bowl. Add cocoa and oil and whisk until smooth.
  • Transfer cocoa mixture to a bowl of an electric mixer. Stir in sugar. Add eggs, one at a time, mixing well after each addition. Add vanilla. Gradually add flour mixture. Pour in chocolate syrup and chocolate chips.
  • Pour batter into prepared 13×9 pan and bake for 25-30 minutes or until done. Let cool before icing.
  • To make the icing: Melt chocolate chips and butter together in a microwave-safe bowl in 30 second intervals on high, stirring well after each segment. (It took me a total of one minute + an additional 10 seconds.) Add corn syrup and stir until smooth. Let sit for 5 minutes before pouring over brownies.

Video

Nutrition

Serving: 1slice | Calories: 492kcal | Carbohydrates: 68g | Protein: 5g | Fat: 24g | Saturated Fat: 13g | Polyunsaturated Fat: 10g | Trans Fat: 1g | Cholesterol: 81mg | Sodium: 340mg | Fiber: 3g | Sugar: 53g

Like chocolate? Be sure to check out these other delicious chocolatey desserts:

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Recipe Rating




Jeanne B

Monday 20th of July 2020

I made these and they were excellent! I did make two changes though. I don’t drink coffee, so I used onyx powder instead, it’s a very dark cocoa powder, like in Oreo cookies. Also, I was in a hurry so I substituted a layer of Nutella for the icing on top, which turned out delicious, of course, and softened the dark intensity of the brownies in a good way. Everyone gobbled these bad brownie boys up!

Lynda

Monday 20th of July 2020

Thanks, Jeanne, for stopping by and leaving your comment. It made me happy to hear that they disappeared!

Jolene

Wednesday 1st of July 2020

Made this recipe, a little over the top with all the sugar oil and butter and the taste wasn’t as good as I was hoping for.

Lynda

Thursday 2nd of July 2020

Thanks for stopping by and leaving a comment. I hate that they were not what you were hoping for. Honestly, at this stage in my life, I probably would find them too sweet and too rich.

Grace

Tuesday 14th of April 2020

Thank you for this recipe! I made these this week ( we added pecans to the icing) and it’s been hands down the best brownies I’ve ever made. Thanks!

Lynda

Wednesday 15th of April 2020

Your comment makes my heart happy! Thank you so much for sharing. I am so delighted you like the recipe. <3

Chris

Friday 3rd of January 2020

Looks amazing. Can’t wait to try them. How much instant coffee instead of expresso? Thanks

Lynda

Saturday 4th of January 2020

I would double the amount.

Ethel Anderson

Tuesday 4th of June 2019

Would like to bake in a larger sheet cake pan would this work

Lynda

Wednesday 5th of June 2019

I am not sure. If you were to do that, you would have to adjust the baking time and/or temperature.