My goodness, isn’t she just gorgeous? I’ve dressed up my classic white cake and vanilla buttercream with one simple improvement: white chocolate mousse filling!

Keep it simple

A few months ago, I was preparing for the new year and new cakes flavors I wanted to add to my repertoire here on the website. I have a quite a few in my Cake Confidence cookbook, and a bazillion coming in my 2022 cookbook, but I wanted to make sure I had plenty on here for you guys to make between cookbooks :).

While doing so, I thought of all the fun and crazy flavors I wanted to add here. But while I was making that list, I remembered something more than a few of you have told me – sometimes the simple recipes are your favorite! We can go all crazy, but nothing beats a good funfetti or chocolate cake, am I right?

I promise you’ll have a good balance of both on here. But let’s begin with a simple white cake with something a little extra: white chocolate mousse!

I know it sounds super simple by way of flavor combinations, but this one is a slam-dunk! It’s perfect for special occasions, or even ANY occasions where you’ll need a cake. It’s decadent enough to really wow everyone but also simple enough to just dive into while sitting at your kitchen counter after lunch.

The recipe for both my white cake and vanilla buttercream are below, but the mousse is separate. You’ll need to go HERE and whip it up (takes less than 15 minutes!) and it will be ready to go inside your cake (or hey, even for a fancy little snack with a scoop of berries on top!).

I cannot wait for you to dive into this one. I usually serve my cakes pretty cold, but for the mousse to be at max-whipped-goodness, I suggest enjoying this one a little closer to room temperature.

That’s it! I can’t wait for you to try this one – I have a feeling it’s going to be one of those go-to classics for years to come. 🙂

As always, if you make one of my cakes, I’d love to see it! Make sure to tag me @bakingwithblondie on Instagram so I can join in on all the fun!

Happy Baking!

~Mandy

Get the Recipe: White Chocolate Mousse Cake

Simple and divine white cake filled with decadent white chocolate mousse and frosted in classic vanilla buttercream.
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Ingredients
 

Classic White Cake

  • 3/4 cup buttermilk , room temperature
  • 2/3 cup sour cream , room temperature
  • 4 egg whites, room temperature
  • 1/3 cup vegetable oil
  • 1 Tablespoon vanilla
  • 1 15.25oz White Duncan Hines Cake Mix (or any other similar brand will do)

White Chocolate Mousse Filling

  • 1 batch White Chocolate Mousse (recipe is on my website!)

Classic Vanilla Buttercream

  • 3 sticks (or 1 1/2 cups) unsalted butter , left out at room temp for 10-15 minutes
  • 1 pinch salt
  • 1 Tablespoon pure vanilla
  • 1/4 cup heavy cream , (plus more later for thinning)
  • 7 cups powdered sugar

Instructions
 

Classic White Cake

  • Preheat the oven to 325 degrees, then prep three 6” cake rounds with a swipe of shortening and dust of flour to prevent sticking. Set aside.
  • In a large mixing bowl, hand whisk together the buttermilk, sour cream, eggs, oil, and vanilla until thoroughly combined. Sift in the cake mix and whisk until just combined. Do not overmix. Next, split the batter evenly between the prepared cake rounds.
  • Bake for 27-30 minutes until the center is baked through. Remove cake rounds from the oven, then let the cakes cool in the pan for a minute before flipping them out onto a wire rack to cool completely. Wrap and chill cakes flat before assembly.

White Chocolate Mousse Filling

  • Follow the instructions for my White Chocolate Mousse and set aside. (https://bakingwithblondie.com/easy-white-chocolate-mousse/)

Vanilla Buttercream

  • In the bowl of a stand mixer fitted with a paddle attachment, whip up the butter until it’s light and fluffy. Add in the salt, vanilla bean, and heavy cream. Whip up to combine and then scrape down the sides with a spatula.
  • With the stand mixer on low speed, add in the powdered sugar about a half cup at a time. It will be thick. Add in a little more heavy cream to thin it out if needed (1 Tablespoon at a time), and then flip the mixer on high speed for 2 minutes to lighten the color and texture of the buttercream.

Assembly

  • Place a cardboard cake round on a cake turntable.
    Spread on a little bit of buttercream in the center of the round with an angled icing spatula.
    Place down the first chilled cake layer in the center. Add on a thin layer of buttercream on top and smooth it out with an angled icing spatula again.
    Pipe a dam of vanilla buttercream around the outside rim of the cake layer, then pipe in the white chocolate mousse in the center.
    Place the next cake layer on top, then repeat with the rest of the layers – making sure to line the layers up evenly. After adding on the top cake layer, crumb coat the cake by spreading the buttercream in a thin layer around the entire cake. Freeze for 2 minutes to set.
  • Using a wooden spoon, hand-beat out any air bubbles in the remaining buttercreams. Spread on a final layer of white buttercream around the entire cake, using a cake scraper for clean edges and sides.
  • Using a small petal #102 piping tip going vertically, pipe a small herringbone pattern from top to bottom. Repeat around the sides of the cake (you can use a cake scraper to carefully press and indent where you want the lines to go to ensure more straight lines and a good guide as you're piping).
  • With a large pedal piping tip #124, pipe a herringbone pattern crown around the top rim of the cake.
  • Enjoy!