If you have a root beer lover in your house or are looking for a great chocolate cake birthday cake for a birthday, then you'll love this Root Beer Float Cake! This root beer cake tastes just like a classic root beer float, but even better because it's a cake! And it's the ultimate happy birthday cake.

Chocolate cake, flavored with root beer extract, then painted in root beer syrup, making it super moist, with a light, fluffy and not too sweet shortening (Crisco) based icing. The root beer cake is topped with marshmallow fluff to look like melted ice cream, with a cherry on top! If you are looking for birthday cake recipes, this is your cake!
I spend a lot of time making birthday cakes. At one point in my life, making and decorating a cake could take me 20+ hours. Now-a-days my focus is on the inside of the cake, rather than decorations. And this homemade Root beer float birthday cake has the BEST tasting insides! Whether you are a kid or an adult, if you like root beer, and you are looking for birthday cake recipes, you will LOVE this cake!
I wanted to try a new technique (gravity defying), so I made this A&W Gravity Defying Root Beer Cake for my husband's birthday a couple of years ago. It soon became his favorite birthday cake and he requested it again this year. It's the ultimate happy birthday cake.

🥘 Ingredients
This cake is a chocolate cake made with root beer extract (You can buy the root beer extract HERE (affiliate link) through Amazon, because it's not easy to find), then it's painted with a reduced root beer syrup for the ultimate in moistness. This Wilton whipped cream buttercream is a light and fluffy shortening based icing that uses meringue powder (you can purchase Wilton Meringue Powder HERE - affiliate link) that isn't too sweet and is the best icing I have ever had - I use it for everything!
I added the marshmallow fluff on top to make it look like the melting ice cream on a root beer float. Although this root beer float birthday cake won't take you 20 hours, it will take you a couple of hours. But trust me, the extra time is worth it.
For this root beer cake, you'll need:
Cake:
- all-purpose flour
- unsweetened cocoa
- baking powder
- baking soda
- milk
- vegetable oil
- eggs
- root beer soda
- powdered sugar (confectioners' sugar)
- shortening* I use Crisco
- white granulated sugar
- salt
- meringue powder
- boiling water
- brown gel icing color
- root beer extract
- maraschino cherry
- marshmallow fluff

📖 Variations & Substitutions
- Frosting: I use my Whipped Cream Buttercream Frosting for this cake, adjusting the liquids to accommodate the liquid from the addition of the root beer extract. This frosting is a PERFECT pairing with this cake. *You will likely have some leftover, so you can make additional cupcakes. It can be stored at room temperature for up to 2 months. When you go to use it again, it will need to be 'fluffed up/whipped with a spatula. *However, if you wanted to try using another frosting, just be sure you compensate for the adding the root beer extract, by reducing the same amount of liquid from the recipe.
- Other frosting options: if you prefer more chocolate and less root beer in the frosting, you could use a different frosting such as my 2 Ingredient White Chocolate Whipped Cream Frosting (Ganache) or my Chocolate Frosting (without butter).
- Cupcakes: ONLY brush the tops of the cupcakes with the root beer coating and bake for half the amount of time (about 15 minutes) or until cake tester comes out clean.
- Bundt cake: Pour batter into bundt cake pan and bake for 50 -60 minutes or until cake tester comes out clean.
🍽Equipment
You'll need 3 -8 inch layer cake pans and an electric mixer (a stand mixer (affiliate links) is best- affiliate link) for this easy root beer float cake.
🌡️Storing
- Storing: Store cake in a sealed container in for up to 2 days at room temperature. Beyond that, it's best to freeze the left overs.
- Freezing: Freeze leftovers in a sealed container for up to 3 months. You can also freeze this cake FULLY DECORATED, in a sealed extra large cake carrier (affiliate link) for up to 1 month.
👪 Serving Size.
This root beer float cake recipe makes 1 - 8 inch -3 layer cake. However, you can half, double or triple the recipe by clicking on the blue serving number and selecting the number of servings you'd like. The ingredient quantities will automatically adjust.
🎥 Video
Combing a cake is a very simple decorating technique and it works very well on this root beer cake. If you've never done it, then check out this video: How to ice and comb a cake *skip the refrigeration part, as this whipped buttercream should NOT be refrigerated!
If you are looking for the ultimate happy birthday cake, this Root Beer Float Cake is it!
⭐ Reviews
Did you make this recipe? Please RATE THE RECIPE below!
What others are saying: "Made this today for my son's birthday and his first response was that it tasted like a tootsie roll - it was delicious! Lots of work but well worth the effort when all is said and done. We went with the icing recipe on this blog and it was exactly what the cake needed- a light and delicate frosting to counter the richness of the cake. Definitely a file for other parties for sure. Thanks for sharing this one!"⭐⭐⭐⭐⭐
And if you love root beer, give my Root Beer Float Fudge a try!



🎂 Root Beer Float Cake Recipe
Ingredients
Cake:
- 2 cups sugar
- 1 ¾ cup all purpose flour
- ¾ cup unsweetened cocoa powder
- 1 ½ teaspoon baking powder
- 1 ½ teaspoon baking soda
- ¾ teaspoon salt
- 1 cup milk
- ½ cup vegetable oil
- 2 large eggs
- 2 TBS root beer extract
- 1 cup boiling water
- 1 cup root beer soda
WHIPPED CREAM BUTTERCREAM FROSTING
Part 1:
- 1 lb. powdered sugar (sifted)
- 2 ½ cups shortening * I use Crisco
Part 2:
- ¾ cup white granulated sugar
- ½ teaspoon salt
- 3 tablespoon meringue powder
- ½ cup (less 2 tbsp) boiling water
- 1-2 teaspoon Brown gel colouring I use Wilton icing coloring
- 1 tablespoon root beer extract
Garnish:
- 1 maraschino cherry
- 2-3 tablespoon marshmallow fluff/marshmallow creme
- 1-3 tablespoon chocolate sprinkles add as many as you desire
Instructions
- Preheat oven to 350 degrees F/175 degrees C. Prepare (I use Wilton Cake release https://amzn.to/3mh24FK -affiliate link) three 8 inch cake pans and set aside.
- In the bowl of a stand mixer (with paddle attachment), combine flour, white granulated sugar, cocoa powder, baking powder, baking soda, and salt.
- Add eggs, milk, oil and root beer extract to the flour mixture. Beat on medium speed for 2 minutes. Slowly stir in boiling water and continue mixing for another minute or until combined.
- Pour cake batter evenly into 3- 8 inch prepared cake pans until each cake pan is ⅔ full. **Batter will be runny
- Bake cake for about 30 minutes or until center of tops spring back when lightly touched. Let cakes cool for 10 minutes before removing from pans to finish cooling onto a wire rack
- While cakes cool, boil root beer in a heavy sauce pan until reduced by half. It will form a syrupy liquid. Brush warm cakes with this root beer concentrate and let finish cooling. Once cool, cover in plastic wrap and refrigerate for several hours or overnight. **this is not critical, but you do get the best results if you do this
Whipped Cream Buttercream:
Part 1:
- Put shortening in bowl of stand mixer and gradually add powdered sugar. Beat about 5 minutes until mixture is very creamy and fluffy. Set this aside.
Part 2:
- In a very clean large bowl mix dry ingredients. Add BOILING water and immediately mix on high speed. Beat until stiff peaks form, about 8 minutes. When mixture begins to get stiff add root beer extract.
- Combine both mixtures and beat together for another 8 minutes. When finished, use a rubber spatula to down beat a little to remove some of the air bubbles. Frosting will be very light and creamy. Cover. DO NOT REFRIGERATE.
- The frosting may be kept at room temperature for 1 month. Whip with a spoon each time you use it to restore fluffiness. * Makes enough to ice this 3 layer 8 inch cake
Assembly & Garnish:
- Transfer cakes to a cake plate. Fill and frost the cake layers then run a comb along the sides of the cake. (see sample method in video)
- Add the marshmallow fluff, then a maraschino cherry in the centre and sprinkle with chocolate sprinkles.
- Serve with vanilla ice cream, if desired.
Notes
Nutrition
🍰More Cake Recipes!
- White Chocolate Pistachio Cake with pistachio pudding filling
- Old Fashioned Gingerbread Cake with Blueberry Cookie Butter Filling
- Lemon Poppy Seed Torte with Raspberry Curd Filling
- Strawberry Jello Angel Food Cake
- Easy Black Forest Cake
- Coconut Lime Tres Leches Cake
- Healthy & Light Carrot Cake Chocolate Mayonnaise Cake
Edith
So yummy
Terri Gilson
Thanks-glad you liked it!
Karly
Yessss! I mean come on, a root beer float in CAKE form!? It's like the king (or queen) of all dessert forms! Need to try this one soon.
Terri Gilson
Thanks, Karly - totally agree!
Ayngelina Brogan
My Dave also loves root beer floats - just ordered one two days ago.
I'm bookmarking this for his birthday!
Terri Gilson
Thanks Ayngelina! He won't be disappointed 🙂
Natalie Browne
I'll have to remember this recipe when my sons birthday comes around. He loves rootbeer floats (who doesn't?, lol). This looks awesome!
Terri Gilson
Thanks, Natalie.. it is very yummy!
Dawn Stewart
Made this today for my son's birthday and his first response was that it tasted like a tootsie roll - it was delicious!
Lots of work but well worth the effort when all is said and done.
We went with the icing recipe on this blog and it was exactly what the cake needed- a light and delicate frosting to counter the richness of the cake. Definitely a file for other parties recipe for sure.
Thanks for sharing this one!
Terri Gilson
Thanks for your comment, Dawn and I'm so glad you all liked it!
Jackie
I can't wait to try... the extract I bought already smells soooo good. Just one thing to clarify,... do you actually put 2 cups of liquid in at the end, the boiling water and the root beer soda?
THanks!
Terri Gilson
Hi Jackie!
I hope you like it! No, you put the 1 cup of boiling water into the batter (the last thing) then bake the cakes.
While that is baking, you boil the 1 cup of root beer on the stove until it's reduced to 1/2.
Then you paint that on the finished cooled cakes and let it sit overnight, wrapped, in the fridge.
I hope it works out well for you! 🙂 Let me know.. Happy baking!
Terri
Jackie
Thanks Terri... I just had to read a little closer... LOL! Thank you!
Terri Gilson
No problem! 🙂
Laura
Looks amazing, I'm going to make it for my son's bday I think!!!
Terri Gilson
Thanks, Laura - you will love it!
Cynthia
Can I use rootbeer oils instead of extract? Do you know what the measurements would be?
Terri Gilson
Hi Cynthia: yes, it can be substituted! "Flavoring oils and extracts can be easily substituted for one another in most recipes. Since flavoring oils are so much more concentrated, you only need a few drops in place of a teaspoon of extract"Check out this oils vs extracts article Enjoy!
Justine McGettigan
I made this for my sons birthday. Everyone loved it! My MIL would like me to make it again this weekend but asked that I amp up the rootbeer flavor. What would you suggest? Adding more rootbeer or more extract?? Thank you
Terri Gilson
Hi Justine,
I'm so glad everyone loved it! I would definitely add more root beer extract- try an additional tablespoon. But you'll need to reduce the milk by 1 tablespoon as well (don't forget that part). I'd love to hear how it turns out!
Enjoy...
Terri
RICHARD
So all I could find at the time is/was Rootbeer Concentrate.
Does anyone know how to convert Concentrate measurement to what it calls for in an extract form?
I know concentrate is usually stronger so?.
How much concentrate would I use to equal the 2 TBS of Rootbeer extract?
RICHARD STEVENS
So here's an update to my recent post an experience with this recipe, author (Ms. Terri) and results?
I had made 2 different cakes this past weekend, Dec. 15th.
2nd XMad dinner.
I made a 7up cake from another site and this Root Beer Float cake.
I hadn't had any that night as I was full from dinner. Dieting.
But I did have the other family members eat a slice. If not at the least try!
Not only were they surprised by the taste of this cake?
They were amazed! I was happy and excited to watch them eat this cake.
Commenting how much it tasted just like a real Root Beer float!
I had left 1/2 of both cakes.
So I'd have something for me and my family at home.
So I finally had a slice.
WOW! I'm a lover of Root Beer soda so. Eating this thick Chocolatey! Root beery! super moist! Super creamy silky Root beer frosting! Oh My Gawdddd!
Thank You Ms. Terri for not only this unique and extremely wonderful, tasty cake!
But also Thank You for personally helping me out and answering my questions online when I needed answers only you could answer.
Being this is your recipe.
THANK YOU SO MUCH!
Shame We can't post pics of what we've either attempted or succeeded in or recipe experience.
Terri Gilson
Hi Richard,
I'm so glad you loved it and it worked out! And I'm also very happy to help - any time. That's what I'm here for 🙂
That's a great suggestion - I'll see if there's a way to add photos! I know you can on Pinterest.
But, in the meantime, please feel free to upload your cake and tag me @foodmeanderings on Instagram! 🙂