Root Beer Layer Cake with Cream Soda Frosting

Root Beer Layer Cake with Cream Soda Frosting

Nathaniel with birthday cake

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Happy birthday, Nathaniel!  My boy turned ten last week. TEN!

But let’s skip the sentimentality — because once it starts, it won’t stop — and jump right in to the cake. (If you ate it, you’d definitely want to jump right into it too.) I asked Nathaniel what sort of cake he wanted, nervously remembering last year’s post-hurricane ginormous Devil’s Food Cake, and he didn’t take long to decide: he wanted the cupcakes his dad got for his birthday, but in layer cake form. So. . .root beer layer cake. With cream soda frosting. Right.

I emailed the blogger who created the amazing recipe for the cupcakes, and asked for her thoughts on transforming her creation into a layer cake. She cheerfully suggested doubling the recipe. I reported back to Nathaniel that all systems were go.

Making this cake was an all-day affair. The reductions are what took the most time; reducing 4 cups of soda down to 1 is no quick task. (Of course the next day, when I was visiting the lovely cheese & gourmet shop Eastern District in Brooklyn, I was shown a handy little bottle of  “cream soda syrup”, which would have been a big help with the frosting. Maybe next year.)

I started with the root beer.

root beer reduction in progress

I kept an eye on it as it simmered, simultaneously assembling ingredients and prepping pans. I didn’t dig into things in earnest, though, until the reduction was done and cooling.

Eggs, oil, and sugar went into the stand mixer.

eggs, oil, and sugar in stand mixer

I added the reduced root beer and some vanilla, skipping the almond extract because I don’t like it. (Baker’s prerogative.)

eggs, oil, and sugar in stand mixer

Did I already mention the healthy aspects of this recipe? There aren’t any. I think once you’re using soda as your flavor foundation, you’ve crossed the line. No substitutions this time; I even used all purpose flour.

flour, baking soda, baking powder, salt

I added the dry ingredients — flour, baking powder, baking soda, and salt — to the contents of the stand mixer, and mixed on low speed.

adding dry to liquid

adding dry to liquid

adding dry to liquid

adding dry to liquid

Time for the root beer! Frothy.

root beer added

And then very, very smooth. Smooth enough that two o’s are not enough. Smoooooooooooth.

smooth batter

I poured the batter into two 9″ round pans, put the first one into the oven, and got the cream soda reduction going. I knew I’d need some time to refrigerate it, but since I was baking the layers separately, I figured I could squeeze it all in and have everything ready at the same time.  So while the cream soda was simmering, and the first layer was baking, I started prepping the ingredients for the pumpkin cheddar muffins.

cheese on scale

What? Pumpkin Cheddar Muffins? Yeah, I decided I also had to make pumpkin cheddar muffins. I had a good reason. But that’s the last you’ll see of that, as I plan to post that very delicious experiment separately. I just wanted you to have a good sense of how I spent my son’s 10th birthday: busy. The cream soda reduction bubbled, the layer cake baked.

cream soda simmering

layer one, done

The next layer went in, and I made the pumpkin muffins while the cream soda syrup, the mixing bowl, and the whisk attachment spent some time in the freezer. When everything seemed ready, it was time for the whipped cream frosting. I’ve made whipped cream before, but not since I acquired my Kitchen Aid mixer, and oh my! what a difference. It was ready so quickly, with no need to constantly check on the consistency.  The only ingredients were heavy cream, vanilla, the cream soda syrup, and a wee bit of sugar. Easy. Stress-free. Rewarding

. making whipped cream frosting

making whipped cream frosting

making whipped cream frosting

making whipped cream frosting

By this time I had both cake layers done and cooled and was ready to begin. As you already know if you’re a regular reader of my blog, decorating is not really part of my skill set. I faced the task ahead with some trepidation.

cake, ready for frosting

I also forgot the key to a smooth layer cake, which is to flip it so the flat sides are facing each other. I was so anxious to cover up the grid lines and that crack that I didn’t even think of it. D’oh! When I had the filling done and had placed the other layer on top, it looked like a gigantic whoopie pie.

giant whoopie pie

I know. Too domey. It was now unnecessarily tall, with an even more unnecessary space in the middle. I just kept at it and hoped that the top layer would eventually sink down a little. It did.

cake, frosted

I smoothed out the frosting as much as I could, bottled up the last of the cream soda syrup to be drizzled on later, and when it was time, we all headed out to the restaurant where we were celebrating Nathaniel’s birthday. Sadly, I didn’t bring my Canon Rebel with me, and had to rely on my iPhone, which at the time was an iPhone 4 and didn’t have the greatest camera in it, especially for a low-lit restaurant. I did the best I could.

Nathaniel looking at root beer layer cake with cream soda frostin

Nathaniel with cake

Here’s how the layers turned out, in the end:

Nathaniel with root beer layer cake with cream soda frosting

So what did I end up with? A delicious cake with sublime frosting, and a very, very happy ten-year-old boy.  Mission accomplished.


Root Beer Layer Cake with Cream Sode Frosting (adapted from Will Cook For Smiles)


2 cups root beer
1 cup root beer syrup (4 cups of root beer simmered down)1/2 cup canola oil
4 eggs, room temperature
2 teaspoons vanilla extract
1 cup brown sugar
4 cups all purpose flour
4 teaspoons baking powder
1 teaspoon baking soda
1/2 teaspoon salt

whipped cream frosting:
2 cups cold heavy whipping cream
2 tablespoons cane sugar
4 teaspoons vanilla extract
4 tablespoons cream soda syrup, made by simmering 2 cups down to 1/2 cup), plus more for drizzling


Simmer 4 cups of root beer down to 1 cup. If you are smart, you’ll also simmer the cream soda down and then put the cream soda syrup in the fridge.

Heat the oven to 350 degrees and spray or grease two 9″ round cake pans.

Using a stand mixer, beat together the eggs, oil, and sugar until well mixed. Add the root beer syrup and vanilla, and beat again.

Separately, whisk together the flour, baking powder, baking soda, and salt. Add it to the bowl in the stand mixer and beat on low speed until incorporated.

Add the root beer, and beat one last time until well mixed.

Pour the batter into cake pans, and bake at 350 for 25-30 minutes. Let the cake cool in the pan for a bit before removing to a wire rack.

While the layers are cooling, make the whipped cream frosting. Chill the metal mixer bowl and the whisk attachment in the freezer for a few minutes. Then pour the heavy cream, cream soda syrup, and vanilla into the chilled bowl and start beating on low, gradually increasing the speed to high every couple of seconds. Slowly add the sugar in while the cream is whippig.

Beat until you get stiff peaks.

Store in the fridge until you’re ready to use it, then frost the cake. Drizzle a little cream soda syrup across it right before serving.


  1. That is one happy face!! I’m so glad the cake turned out good and everyone had a great time!

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