This root beer float cake is everything you love about the classic summertime treat in cake form! Using a box of cake mix makes this moist, single-layer marble cake recipe extra easy. It’s filled with chocolate cream cheese frosting and topped with pillowy root beer whipped cream. Best served drizzled with hot fudge sauce and finished with a maraschino cherry, just like an original float!
If you’ve ever had the famous bottomless root beer floats from Red Robin, I think you’re going to love this copycat cake recipe! I knew I wanted it to be a marble cake, so I adapted my homemade recipe with a box of white cake mix for ease. This root beer cake is equal parts moist vanilla cake and fudgy chocolate cake infused with root beer extract. The cake is then filled with chocolate cream cheese frosting and topped with fluffy root beer whipped cream.
This is the perfect root beer float cake for summer! It’s full of nostalgic flavor, great for a fun barbecue dessert, summer celebration, or birthday cake. Melt extra chocolate or warm up hot fudge sauce to drizzle over the finished cake, and don’t forget a cherry on top. For another ice cream parlor favorite, try my no-bake banana split pie.
Why Bake This Root Beer Float Cake
- Unmistakable root beer flavor. I opted to use root beer extract to flavor my cake, as opposed to real root beer. Not only is the flavor stronger, but it doesn’t water down the cake or whipped topping.
- One batter, two cake flavors. A box of cake mix makes it easy to prepare the batter for the marble cake. Afterward, simply set aside a portion of the batter to combine with melted chocolate for the chocolate-flavored cake.
- Easy to adapt. It’s super simple to make whipped cream from scratch. But if you wanted to take another shortcut, you could easily use a tub of Cool Whip mixed with root beer extract instead of homemade whipped cream for the topping.
Ingredient Notes
These are the key ingredients needed to make this fun summer dessert, why you’ll need them, and possible substitutions. Refer to the recipe card for the complete recipe, ingredients list, and measurements.
- White Cake Mix – Your favorite brand of boxed white cake mix. Using a cake mix means there’s no need to individually measure or weigh out the dry ingredients for the cake batter.
- Oil – I generally like to use vegetable oil in my cake recipes rather than butter. It yields a moist, lighter, and more tender crumb.
- Chocolate Chips – While I usually insist on chocolate bars or baking bars for melting, chocolate chips work perfectly here. Rather than flavoring the chocolate cake portion with cocoa powder, I prefer melted chocolate for a fudgier, almost brownie-like texture.
- Root Beer Extract – I use root beer extract in the chocolate cake and to infuse the homemade whipped cream topping.
- Cream Cheese – For the sweet-tangy chocolate filling. Use a brick of full-fat cream cheese and soften it to room temperature for a smooth, lump-free frosting.
- Cocoa Powder – Use natural cocoa powder or Dutch-processed cocoa powder for a darker filling with a more intensely fudgy flavor.
- Heavy Whipping Cream – Cold from the fridge so that it whips easily for the topping. Make sure it’s full-fat heavy cream or whipping cream, and not pouring cream.
How to Make a Root Beer Cake
Follow the steps below to prepare and layer this deliciously fudgy root beer float cake.
- Swirl the cake batter. Start by mixing the cake mix, eggs, milk, oil, and vanilla to make the batter. In a separate bowl, melt the chocolate (see how to melt chocolate chips) and stir in 2 teaspoons of root beer extract. Divide the cake batter in half, and mix the melted chocolate into one portion. Pour both batters into a lined 9×13-inch baking dish and swirl them together using a knife.
- Bake. Bake the marble cake at 350ºF for 20-25 minutes, then cool completely. Once cooled, use a serrated knife to carefully cut the sheet cake in half horizontally. I find it helpful to slide a flat cookie sheet in between the two layers, setting the top half aside.
- Add the chocolate filling. Meanwhile, beat cream cheese in a bowl for 1-2 minutes, and slowly add the powdered sugar, cocoa powder, and vanilla to make the frosting. Spread the chocolate frosting evenly over the bottom cake layer. Gently place the top cake layer over the filling. Refrigerate the cake until it’s time to add the whipped cream.
Root Beer Whipped Cream
I recommend adding the whipped cream topping when you’re ready to serve.
- Make the topping. Start with cold ingredients and tools. Chill the mixing bowl and whisk in the freezer for 10 minutes. To the cold bowl, add fridge-cold heavy whipping cream, then use a mixer to beat until bubbly. Slowly add the powdered sugar and root beer extract, then beat the whipped cream until soft peaks start to form.
- Top and serve. Spread the prepared whip over the top of the cake. Slice and serve with hot fudge sauce and cherries!
Tips for the Best Cake
- Soften the cream cheese. The softer cream cheese incorporates so much more easily with the other ingredients. We don’t want a lumpy filling. You can even microwave it for 20 seconds or so before you make the filling, if needed.
- Melt the chocolate in intervals. When melting the chocolate, do so at 50% power in 30-second increments to prevent it from seizing up.
- Check the cake for doneness. To check that the cake is done baking, insert a toothpick into the center. When it comes out clean, it’s ready to go.
- To release the cake from the pan, run a knife around the outside edges of the cake. Place a piece of parchment paper over top and flip the pan over. Tap the bottom of the pan to release the cake.
- Use cold tools when making whipped cream. Chill the bowl and whisk. The colder bowl and whisk attachment make a lighter, fluffier whipped cream.
- Go easy with the extract. Root beer extract can be overbearing if you add too much. I suggest adding only a couple of drops in the beginning, then adding more to taste. You can always add more, but you can’t take it away.
How to Store
- Refrigerate. The fully assembled root beer float cake will last for 3-4 days in the fridge. It must be stored in the fridge because of the whipped topping.
- Freeze. I recommend freezing the baked, cooled marble cake as opposed to the fully finished float cake. Double wrap the cake in plastic wrap, and freeze it for up to 2 months. Thaw the cake at room temperature before slicing it in half and assembling as usual.
More Summer Dessert Recipes
Root Beer Float Cake
- Prep Time: 30 minutes
- Cook Time: 23 minutes
- Total Time: 53 minutes
- Yield: 15 slices
- Category: Cake
- Method: Oven
- Cuisine: American
Description
This root beer float cake is a moist, single-layer marble cake filled with chocolate cream cheese frosting and topped with root beer whipped cream.
Ingredients
For the Cake:
- 1 box (15oz) white cake mix
- 3 large eggs
- ¾ cup milk
- ½ cup vegetable oil
- 1 teaspoon vanilla extract
- ½ cup chocolate chips
- 2 tablespoons milk
- 2 teaspoons root beer extract
For the Chocolate Layer:
- 8 ounces cream cheese, softened
- 2 cups powdered sugar
- 2 tablespoons cocoa powder
- 1 teaspoon vanilla extract
For the Whipped Topping:
- 1 ½ cups heavy whipping cream
- 3/4 cup powdered sugar
- ½ teaspoon root beer extract
- Cherries for garnish
- Hot fudge sauce for garnish
Instructions
For the Cake:
- Preheat the oven to 350°F. Line a 9-inch by 13-inch baking sheet/pan with parchment paper and spray with cooking spray.
- In a large mixing bowl, combine the cake mix, eggs, milk, vegetable oil, and vanilla extract and stir until well combined.
- In a microwave-safe bowl, combine the chocolate chips and milk and melt in 30-second increments, stirring occasionally until the chocolate is melted and smooth.
- Stir 2 teaspoons of root beer extract into the melted chocolate and mix until smooth.
- Divide the cake batter into halves. Stir the melted chocolate into half of the cake batter and mix until smooth.
- Pour both cake batters into your pan, swirling the cake mix together with a knife.
- Bake at 350°F for 20-25 minutes. To test the cake for doneness, insert a toothpick into the center of the cake. If the toothpick comes out clean, your cake is done. Allow the cake to cool completely.
- Once cooled, run a knife around the outside edges of the cake. Place a piece of parchment paper on your countertop and quickly flip the pan over, tapping the bottom of the pan to help release the cake from the pan. Once released, use the parchment paper to help flip the cake back over so it is right-side up. Use a large serrated knife and divide the cake in half.
- Take a flat cookie sheet and slide it between the layers to separate them. Set the top of the cake aside. Gently place the bottom of the cake back in the pan.
For the Chocolate Layer:
- Remove the cream cheese from the wrapper and microwave for 20 seconds. Beat the softened cream cheese for 1-2 minutes to remove the lumps.
- Slowly add the powdered sugar, one cup at a time, followed by the cocoa powder, scraping down the bowl as needed. The cream cheese will start to thicken. Add the vanilla extract and mix until it’s well combined.
- Gently spread the cream cheese over the bottom layer of the cake. Then, slowly place the top layer of cake back into the pan, gently pressing into the cream cheese.
- Refrigerate the cake until you’re ready to add the whipped topping.
For the Topping:
- Chill the mixing bowl and whisk into the freezer for 5-10 minutes to chill.
- Pour the heavy whipping cream into the chilled bowl and use an electric mixer to beat the heavy cream on medium-high speed until the cream gets bubbly. Slowly add the powdered sugar and root beer extract and continue beating on high speed until peaks start to form.
- Spread the whipped cream over the top of the cake.
- This cake must be refrigerated. Serve with drizzled hot fudge sauce and a cherry on top.
Nutrition
- Serving Size: 1 slice
- Calories: 451
- Sugar: 26 g
- Sodium: 149.6 mg
- Fat: 26.7 g
- Carbohydrates: 50.5 g
- Fiber: 0.7 g
- Protein: 4.9 g
- Cholesterol: 79.7 mg
I am making this and the ingredient amounts seem off for topping and chocolate layer. Did anyone else find that too?
Hi Tricia, I sent you an email. I need some more clarification 🙂
I think I will try this without cutting the cake in half and instead place the chocolate ganache on top of the cake and then top with the whipped cream. Your recipe sounds delicious!
Please clarify – how much 10X sugar goes into the topping?
Please clarify. How much 10x sugar goes into the topping?
Hi Terri, it’s 1/2 cup + 2 tablespoons!
This recipe looks delish. Please clarify topping ingredients. Should second “whipping cream” be 10x sugar? I want to make this asap. Thanks!
Hi Terri, yes 10x sugar is another name for powdered sugar
Root beer floats are one of my favorite treats! I think this is the cake for me!
You had me at “every bite is rich with flavor and texture”. Me love me a root beer float!