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Chocolate Root Beer Float Cake

My new and improved Chocolate Root Beer Float Cake recipe has been updated (6/29/2022)! I’ve tweaked a few things in this recipe, plus added some process shots to help you bake and decorate this jaw-dropping cake right in your home kitchen.

Chocolate Root Beer Float Cake white open shot on cake teal cake pedestal.

If you love the soda shop classic root beer float, you’ll love the three layers of decadent chocolate-root beer flavored cake layers, filled with vanilla ice cream frosting, and frosted with root beer flavored chocolate frosting. And if that weren’t enough, I’ve topped it with root beer chocolate drip, more vanilla ice cream frosting and rainbow sprinkles! 

Chocolate Root Beer Float Cake overhead shot on cake pedestal with cake plated and sprinkles.
Chocolate Root Beer Float Cake three quarter angle close up of top cake decoration.

What Is Simple Syrup

Simple syrup is equal parts water and sugar and is great for incorporating moistness and flavor to any cake. Have fun with different flavors by using extracts, oils, liqueur and spices.

  • Flavor oils: use 1 teaspoon
  • Extracts: use 2 teaspoons
  • Liqueurs: use 1 to 3 tablespoons
Chocolate Root Beer Float close up of cake on pedestal.

Chocolate Root Beer Float Cake Ingredients

  • All-purpose flour: is super versatile and has more protein content than cake flour. For cakes that require more structure, such as this chocolate cake, all-purpose flour is a great choice.
  • Dutch-processed cocoa powder: has a higher pH which neutralizes its acids and helps balance out the flavor.
  • Baking powder: is a mixture of baking soda and cornstarch. It works twice, firstly when it comes into contact with a liquid and second, when it comes in contact with heat.
  • Salt: enhances flavor.
  • Buttermilk: adds a tangy flavor to the cake as well as tenderizes the cakes crumb. Buttermilk is also an acidic ingredient and will react with the baking powder mentioned above to create a fluffy cake.
  • Root beer: helps with the flavor.
  • Unsalted butter: is rich in flavor and the fat coats the flour proteins inhibiting their ability to form a strong gluten connection which in turn, creates a tender cake.
  • Brown sugar: is granulated sugar that has been combined with molasses.
  • Root beer flavor oil: I used LorAnn Root Beer Flavoring for this cake but you can also use root beer extract and follow the substitution amount required.
  • Eggs: help bind, thicken, emulsify and leaven.
  • Sour cream: helps to make the cake tender and is also an acidic ingredient which will react with the baking powder and buttermilk.
  • Baking soda: is an alkali which means it should be used with an acidic ingredient (buttermilk, sour cream, molasses and brown sugar) which produces carbon dioxide. Baking soda helps leaven the cake and browns it as well.
  • Distilled white vinegar: when vinegar is combined with the baking soda it creates a chemical reaction creating carbon dioxide which creates a fluffy and moist cake texture.

Vanilla Ice Cream Frosting

This super fun frosting looks and tasted like vanilla ice cream! And it should because it’s made with, you guessed it! Vanilla ice cream!

How To Make Root Beer Chocolate Frosting

If you’ve never made frosting in a food processor now is your chance! And best of all it’s super easy and quick.

  • Place butter, sugar, cream, root beer flavoring and salt in a bowl of a food processor and pulse until combined, about 1 minute.
  • Melt chocolate in a microwave in 30 second intervals, stirring after each interval until melted. Cool melted chocolate slightly about 10 minutes. Add the melted chocolate to the food processor and process until smooth, about 1 minute. If the frosting is too soft refrigerate it until it firms up a bit. This frosting is the best consistency if used right away.

Cake Assembly

  • Fit a piping bag with a round piping tip or coupler and fill the piping bag with about 1 cup buttercream.
  • Pipe a buttercream dam around the outer edge of the cake.
  • Fill the center with half of the filling and spread out in an even layer with a small offset cake spatula.
  • Place the second cake layer on top and gently press to adhere to the bottom cake layer. 
  • Pipe a buttercream dam around the outer edge and spread the remaining filling out in an even layer until it reaches the buttercream dam.
  • Add the third and final cake layer (bottom side up) on top and gently press to adhere.
Chocolate Root Beer Float overhead shot of filling.

Crumb Coating

The first coat of frosting is called the crumb coat. This helps hold in the loose crumbs and prevents the crumbs from getting into the final layer of frosting.

  1. Apply a thin layer of buttercream over the top and sides of the cake, creating a crumb coat.
  2. Chill the crumb coated cake in the refrigerator for 30 minutes.
Chocolate Root Beer Float crumb coated.

Icing The Cake

  1. Apply a large dollop of chocolate frosting on top of the cake and spread out evenly.
  2. Line an 8-inch round acrylic disc with parchment paper with a bit of chocolate frosting. Line up the acrylic disc with the bottom cake board and gently press on to the top of the cake to adhere.
  3. Gently press a cake comb against the side of the cake and slowly rotate the cake turntable all the way around to create a decorative finish on the side of the cake. (Make sure your cake comb is the right size for your cake. If the cake comb is too large the acrylic disc might get in the way.) Chill the cake in the refrigerator for at least 15 minutes. 

Perfect Chocolate Drips!

  • Chill your cake before adding the drips. The chilled cake will help slow down the drips, giving you more control.
  • Make sure the chocolate is the right temperature. It should be fluid but not warm.
  • Find the spot on your cake that will be the back and run a test drip on it. If the drip slips off the cake it’s too hot. If the drips clump, it’s too cold.
  • For more controlled drips, use a spoon or a squeeze bottle and add the drips to the sides of the cake first. I prefer using a spoon for my drips.
  • Once you have your side drips done, gently pour the remaining chocolate on the top and spread out until it meets the edges. Reheat the chocolate if needed.
Chocolate Root Beer Float Cake with chocolate drip.

Cake Decorating Tools

  • 8 inch round cake board
  • Cake turntable
  • Pastry brush
  • Piping bag
  • Coupler or round piping tip
  • Small offset cake spatula
  • 8-inch round acrylic disc
  • Parchment paper
  • Cake comb 
  • Ice cream scoop
Chocolate Root Beer Float Cake cake slices on plates.

Chocolate Root Beer Float Cake Baking Schedule

  • Day 1: Bake cake layers and make simple syrup.
  • Day 2: Prepare vanilla and chocolate frosting, assemble, decorate, and serve
Chocolate Root Beer Float Cake close up slice of cake.

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Chocolate Root Beer Float Cake close up shot of cake layers.

Suggested Recipes

Adapted from The Sweetapolita Bakebook by Rosie Alyea

Chocolate Root Beer Float Cake white open shot on cake teal cake pedestal.

Chocolate Root Beer Float Cake

Yield: 12
Prep Time: 2 hours
Cook Time: 30 minutes
Additional Time: 1 hour
Total Time: 3 hours 30 minutes

Three decadent layers of chocolate-root beer cake, soaked in root beer simple syrup, filled with vanilla ice cream frosting, and frosted with chocolate-root beer frosting. Lastly, it's garnished with root beer chocolate drip, more vanilla ice cream frosting and rainbow sprinkles!

Ingredients

SPECIAL TOOLS

  • 3 8-inches round cake pans
  • Nonstick baking spray
  • 4 cup liquid measuring cup
  • Stand mixer
  • Sieve
  • Food processor
  • 8 inch round cake board
  • Cake turntable
  • Pastry brush
  • Piping bag
  • Coupler or round piping tip
  • Small offset cake spatula
  • 8-inch round acrylic disc
  • Parchment paper
  • Cake comb
  • Ice cream scoop

ROOT BEER SIMPLE SYRUP

  • ½ cup (3.5 ounces) granulated sugar
  • ½ cup water
  • 1 teaspoon root beer flavor oil or 2 teaspoons root beer extract

CHOCOLATE CAKE

  • 2 1/3 (13 ounces) cups all-purpose flour
  • 1 cup (3 ounces) Dutch-process dark cocoa
  • 1 ½ teaspoons baking powder
  • ¾ teaspoon table salt
  • ½ cup (4 ounces) buttermilk, at room temperature
  • 12 ounces root beer
  • 1 cup (16 tablespoons) unsalted butter, at room temperature
  • 2 cups (14 ounces) light brown sugar, packed
  • 1 teaspoon root beer flavor oil or 2 teaspoons root beer extract
  • 4 large eggs, at room temperature
  • ¼ cup sour cream, at room temperature
  • 1 ½ teaspoons baking soda
  • 2 teaspoons distilled white vinegar

VANILLA ICE CREAM FROSTING

  • 1 cup (16 tablespoons) unsalted butter, at room temperature
  • ¼ cup (4 tablespoons) shortening
  • Pinch of salt
  • 3 ¼ cups (13 ounces) powdered sugar, sifted
  • ½ cup (4 ounces) heavy cream
  • 2 teaspoons vanilla extract
  • ½ cup melted vanilla ice cream

CHOCOLATE ROOT BEER FROSTING

  • 2 cups (32 tablespoons) butter, at room temperature
  • 4 cups (16 ounces) powdered sugar
  • 1/3 cup (2.6 ounces)heavy cream
  • 1 teaspoon root beer flavor oil or 2 teaspoons root beer extract
  • Pinch of salt
  • 7 ounces bittersweet chocolate, chopped

CHOCOLATE ROOT BEER DRIP

  • 6 ounces semisweet chocolate, chopped
  • 3/4 cup (6 ounces) heavy cream
  • 2 tablespoons unsalted butter, cut into 8 cubes
  • 1 teaspoon root beer flavor oil or 2 teaspoons root beer extract

GARNISH

  • Rainbow sprinkles
  • Maraschino cherry

Instructions

ROOT BEER SIMPLE SYRUP

  1. In a small saucepan over medium heat, bring the sugar and water to a boil. Cook until all the sugar has dissolved and syrup begins to thicken, about 2 minutes.
  2. Remove the pan from the heat and stir in root beer oil and root beer extract. Let syrup cool completely.

CHOCOLATE CAKE

  1. Adjust an oven rack to the center position and heat the oven to 350 degrees. Spray 3 8-inch round cake pans with non-stick baking spray and set aside.
  2. In a large bowl whisk together the flour, cocoa powder, baking powder and salt. In a 4 cup liquid measuring cup, whisk together the buttermilk and root beer and set aside.
  3. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter and brown sugar together on medium speed until light and fluffy, about 8 minutes. Add the root beer oil or root beer extract and beat to combine. Add the eggs one at a time, mixing after each addition until just combined. Scrape down the sides of the bowl with a rubber spatula as needed.
  4. Remove the bowl from the mixer and with a rubber spatula, fold in the flour mixture in 3 additions, alternating with the buttermilk mixture in 2 additions. Fold in the sour cream.
  5. In a small bowl, whisk the baking soda and vinegar together and quickly fold into the batter. Don’t over mix. Divide the batter evenly in the prepared cake pans.
  6. Bake for 20 to 25 minutes or until a cake tester inserted in the center of the cakes comes out with a few moist crumbs attached. Let the cake layers cool in their pans on wire racks for 10 minutes. Loosen the sides of the cakes and invert on to wire racks to cool completely.

VANILLA ICE CREAM FROSTING

  1. In the bowl of a stand mixer fitted with the paddle attachment, beat the butter, shortening and salt on medium speed until light and creamy, about 8 minutes. Add sifted powdered sugar, heavy cream, vanilla extract or vanilla paste and melted ice cream.
  2. Reduce the speed to the lowest setting and beat for 1 minute. Increase the speed to medium-high and beat until very light and fluffy, about 6 minutes.

CHOCOLATE ROOT BEER FROSTING

  1. Place butter, sugar, cream, root beer flavoring and salt in a bowl of a food processor and pulse until combined, about 1 minute.
  2. Melt chocolate in a microwave in 30 second intervals, stirring after each interval until melted. Cool melted chocolate slightly about 10 minutes. Add the melted chocolate to the food processor and process until smooth, about 1 minute. If the frosting is too soft refrigerate it until it firms up a bit. This frosting is the best consistency if used right away.

CHOCOLATE ROOT BEER DRIP

  1. Place chopped chocolate in a heatproof bowl. In a small saucepan, over medium heat, bring the cream to a simmer. Pour hot cream over the chopped chocolate and stir until the chocolate has melted and is smooth. Add the butter and root beer extract and stir until melted and combined. Cool on the counter for about 10 to 15 minutes before using.

ASSEMBLE

  1. Trim cakes so the are flat and the tops are evenly straight. With a pastry brush, spread a generous amount of simple syrup over the top of each cake layer.
  2. Center one of cake layers on a cake board and place the cake board on a cake turntable.
  3. Fit a piping bag with a coupler or round piping tip and fill with about 1 cup chocolate frosting. Pipe a frosting dam around the edge of the first layer of cake. Using a small offset cake spatula, spread about 1/2 cup of the ice cream frosting over the top, spreading out in an even layer until it reaches the frosting dam. Repeat this process with the remaining cake layers. Place the last cake layer bottom side up. Reserve the remaining ice cream frosting for decorating the top of the cake.

CRUMB COAT

  1. Apply a thin layer of chocolate frosting over the top and sides of the cake and chill in the refrigerator for 15 minutes.

DECORATING

  1. Apply a large dollop of chocolate frosting on top of the cake and spread out evenly. Line an 8-inch round acrylic disc with parchment paper with a bit of chocolate frosting. Line up the acrylic disc with the bottom cake board and gently press on to the top of the cake to adhere.
  2. Gently press a cake comb against the side of the cake and slowly rotate the cake turntable all the way around to create a decorative finish on the side of the cake. (Make sure your cake comb is the right size for your cake. If the cake comb is too large the acrylic disc might get in the way.) Chill the cake in the refrigerator for at least 15 minutes. While the cake is chilling, prepare the Chocolate Root Beer Drip.

CHOCOLATE ROOT BEER DRIP

  1. Place chopped chocolate in a heatproof bowl. In a small saucepan, over medium heat, bring the cream to a simmer. Pour hot cream over the chopped chocolate and stir until the chocolate has melted and is smooth. Add the butter and root beer extract and stir until melted and combined. Cool on the counter for about 10 to 15 minutes before using.
  2. Remove the arylic disc by inserting a small offset spatula under the disc and gently turning the turntable until the disc releases and peel off the parchment paper. Add chocolate drip to a squeeze bottle, piping bag or use a spoon to apply to the sides of the cake. Pour more chocolate glaze in the center of the cake and spread to meet the edges of the dripped chocolate. (Save the remaining chocolate glaze for decorating the top of the cake.) Chill the cake for 15 minutes in the refrigerator before decorating the top of the cake.
  3. Using an ice cream scoop, scoop the remaining vanilla ice cream frosting onto the top of the cake. Drizzle the remaining glaze on top of the cake and sprinkle with rainbow sprinkles and add a cherry on top. Transfer cake to a cake pedestal and serve.



Notes

Assembled cake will keep at a cool room temperature in an airtight container for up to 1 day or in the refrigerator for up to 3 days. Bring to room temperature before serving.

Root beer simple syrup can be made up to a week in advance, stored in an airtight container in the refrigerator.

Cake layers can be made up to 3 days in advance, wrapped in plasti wrap, stored in an airtight container in the refrigerator.

Nutrition Information:
Yield: 12 Serving Size: 1
Amount Per Serving: Calories: 734Total Fat: 40gSaturated Fat: 16gTrans Fat: 0gUnsaturated Fat: 22gCholesterol: 138mgSodium: 643mgCarbohydrates: 88gFiber: 4gSugar: 65gProtein: 9g

*Nutrition information is an estimate and will vary.*

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