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.
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.
🥘 Ingredients
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 teaspoon vanilla
- ¼ teaspoon salt
Brownie Cake Batter
- 1½ cups all-purpose flour
- 1 teaspoon baking powder
- 1 teaspoon salt
- 2 tablespoons espresso powder
- 10 tablespoons butter (= 1 stick + 2 tablespoons)
- ¾ cup baking cocoa
- ¼ cup vegetable oil
- 2 cups sugar
- 4 large eggs
- 2 teaspoons vanilla extract
- ⅔ cup chocolate chips
- Chocolate Syrup
Chocolate Icing
- 1¼ cups chocolate chips
- 3 tablespoons corn syrup
- 1 stick butter
🔪How To Make a Chocolate Brownie Cake
Start off by making a simple chocolate syrup. Just sugar, cocoa, water, vanilla, and a little salt.
The reason to make the syrup first is that it has to come to a boil and then cool. It will thicken some during the cooling period.
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.
⏲️ Baking Time
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.
📖 Recipe
Chocolate Brownie Cake
Ingredients
Chocolate Syrup
- ¼ cup unsweetened cocoa powder
- ½ cup water
- 1 cup sugar
- 1 teaspoon vanilla
- ¼ teaspoon salt
Brownie Batter
- 1½ cups all-purpose flour
- 1 teaspoon baking powder
- 1 teaspoon salt
- 2 tabelspoons espresso powder
- 10 Tablespoons butter (1 stick + 2 tablespoons)
- ¾ cup baking cocoa
- ¼ cup vegetable oil
- 2 cups sugar
- 4 large eggs
- 2 teaspoons vanilla extract
- ⅔ cups chocolate chips
- Chocolate Syrup
Chocolate Icing
- 1¼ cups chocolate chips
- 3 tablespoons corn syrup
- ½ cup butter (1 stick)
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
Like chocolate? Be sure to check out these other delicious chocolatey desserts:
- Nutella Bread (aka Chocolate Bread) – Luscious Nutella enrobed in a homemade sweet dough – it’s great for breakfast, snack, and dessert!
- Brown Sugar Blondies – This is the recipe for those who really want a brownie but can’t have chocolate.
Kathy Graziano says
can you use fondant frosting on it need to decorate for a school project
Lynda says
You probably could. If my child had a school project, I think I would just use a box of cake mix to keep expenses down rather than make this from scratch.
doris stuart says
well the brownie cake looks good but i would what the one person did was omitt the espresso powder but i wouldnt add anything in place of it. dont drink coffee and dont like the stuff with with coffee in it. and i woud make my own frosting to put on it . thanks
Jeanne B says
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 says
Thanks, Jeanne, for stopping by and leaving your comment. It made me happy to hear that they disappeared!
Jolene says
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 says
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 says
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 says
Your comment makes my heart happy! Thank you so much for sharing. I am so delighted you like the recipe. <3
Chris says
Looks amazing. Can’t wait to try them. How much instant coffee instead of expresso?
Thanks
Lynda says
I would double the amount.
Ethel Anderson says
Would like to bake in a larger sheet cake pan would this work
Lynda says
I am not sure. If you were to do that, you would have to adjust the baking time and/or temperature.