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Easiest Ever Brownie Birthday Cake Idea


This Brownie Birthday Cake Idea couldn’t get any easier. It’s made with your favorite boxed brownie mix (really!), and simple powdered sugar. I love to rethink old favorites and make them more memorable. And stacking brownies on top of each other turns this into a unique dessert that is perfect for easy entertaining.

A pan of brownies stacked like a tiered cake and topped with powdered sugar on a silver cake stand surrounded by fresh flowers.
Let’s make this gorgeous and easy-to-make brownie cake!

A fun alternative to a traditional birthday cake

What is a brownie cake you might ask? It’s a pan of brownies stacked to look like a tiered cake. Really. It’s that simple.

I love to serve things in a new way at the parties I throw and this birthday brownie idea is such a fun way to add a special detail that the guests will love. 

Related: Beer Brownies

Brownie towers can be seen taking the place of wedding and birthday cakes often, but of course, I had to make it even more simple. Instead of a brownies tower for a birthday try a tiered brownie cake instead.

Sure, you can serve a plain old cake. But why not serve a brownie cake? It’s something you don’t see every day, everyone (well, just about everyone) loves brownies and it’s SO easy. So just make one, ok? 

Just look at how cute it is!


A bag of boxed brownie mix and the ingredients to make a brownie birthday cake on a wooden cutting board.
This is what you’ll need to make a birthday cake from brownie mix.

To make this 3 tiered brownie cake, I used two boxed brownie mixes. Stupid easy.

Just make sure to read the back of the box to see what other ingredients are needed for your mix.

Mine needed eggs, oil, and water.

And powdered sugar gives it a more finished look that is easy and perfect for people who don’t decorate cakes well. (That’s me. I am a terrible decorator!)

How to Make a Brownie Birthday Cake

Close up image of a three tiered brownie cake on a silver cake plate.

Step 1

Prepare the brownie mixes as directed on the box and then pour them evenly into a 9“, 6″ and 4″ cake pan.

They sometimes sell cake pan sets but I really think the top tier looks cutest when it is 4″ instead of 6″. That’s totally my personal opinion though…

Also I am a big fan of using what you already have and I had a 4″ pan.

Step 2

Once the brownies are cooked through, let them cool and remove them from the pans.

Step 3

Level the cakes. Because I am not a baker, I carried my cakes next door to have my fabulous neighbor level them for me.

This brownie cake is totally rustic so I probably could have done it myself, but I knew she would do it right the first time.

I know my limits and work around them…And I’m super lucky to have such talented people in my life. 

Since this is a “naked” cake or brownie cake, rather, you’ll see every little crack or crevice. Which isn’t bad, just know this will be rustic!

I also could have had her make the top tier the same thickness as the other brownie layers, but I wasn’t that worried about it.

A brownie birthday cake idea topped with an air plant.

Step 4

Stack the brownie layers.

Decide what you want to serve the cake on and then place the largest brownie layer as the base.

Try to stack the other layers in the center on top of each other.

Step 5

Top with powdered sugar.

What I love about a brownie cake is that there is no frosting. Frosting can get super messy and is another chance for something to go wrong.

I am the world’s worst froster. I can’t put on a crumb coat to save my life. So anyway around having to use frosting is the best. Don’t get me wrong, I’ll eat frosting all day long. I just don’t want to have to put it on something.

If you want to frost this brownie birthday cake idea it would be delicious with my Vanilla Buttercream or my Cool Whip Frosting!

I used a light dusting of powdered sugar to finish the cake and it was all it needed. And to add an extra little boho touch, since this was part of my boho baby shower, I topped the brownie cake with a simple air plant. 


Here’s what you’ll need to make this brownie birthday cake idea:

I also have an entire shop dedicated to some of my baking favorites that will help you perfect delicious desserts like this one every time!


  • If you’ve never leveled a cake before (and you don’t have a lovely neighbor to help), check out this tutorial from Serious Eats.
  • If you don’t want to worry about leveling, you could make a brownie tower instead by cutting pan of brownies into individual sizes and then carefully stacking them in a circular tower on top of each other.
A birthday cake made from a brownie mix on a silver cake plate, surrounded by air plants and decorative stones.

This brownie cake is so easy to make but totally different from what you would normally find at a party. Plus it looks super celebratory. So instead of making your brownies in a dumb old pan, next time make this tiered brownie cake instead.

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More Easy Desserts from a Boxed Mix

A square collage of three images featuring a three-tiered brownie cake topped with an air plant.

Decadent Brownie Birthday Cake Idea

Skip the usual cake and treat guests to this brownie cake instead. It's so easy and so delicious!
5 from 1 vote
Print Pin Rate
Course: Dessert
Cuisine: American
Prep Time: 30 minutes
Cook Time: 45 minutes
Total Time: 1 hour 15 minutes
Servings: 8 servings


  • Cake pans of various sizes: 9", 6" and 4".
  • Cake leveler
  • Sifter



  • Prepare the brownie mixes according to the instructions on the box.
  • When they are done, let them cool and remove them from the pans.
  • Level the brownie cakes.
  • Stack the brownie layers.
  • Top with powdered sugar.


***Nutrition will vary widely based on which brownie mix you use, as well as the ingredients needed to make them.
If you’ve never leveled a cake before check out this tutorial from Serious Eats.
If you don’t want to worry about leveling, you could make a brownie tower instead by cutting a pan of brownies into individual sizes and then carefully stacking them in a circular tower on top of each other.
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    1. Do you need supports under each layer to prevent the layers sinking into one another?

    2. My granddaughter asked for brownies for her birthday cake- how boring! But I saw your 3 tiered brown one cake! It was a hit!
      Wish I could send a pic of it!

    3. Do you have the details on the cook time and temperature for the different sizes?

      1. I don’t! I think it will depend on the size pans that you use. For the smallest size, I kept checking it with a cake testing pick. But it was thicker than the traditional cake pan so they took a similar time.

    5 from 1 vote (1 rating without comment)

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