Neapolitan Birthday Cake with Marshmallow Frosting [recipe]

Birthday Cake 5

This was a cake I made for a friend’s birthday last month. I was short on time so I decided to use boxed cake mix (surprise! those of you who ate the cake, betcha didn’t know it wasn’t from scratch!) and only make the filling and frosting myself. I’ve forgotten how EASY it is to make cake from a box mix, kind of nostalgic and brought me right back to the high school days when my friends and I loved to get together and bake brownies and cakes. This cake was meant to feed at least 20 people so the hardest part was to settle on a flavor…death by chocolate? vanilla? red velvet? In the end I went with neapolitan- chocolate, vanilla, and strawberry all in one cake, this will surely please everyone.

I used Betty Crocker SuperMoist cake mix. For this particular cake, I used one box of chocolate fudge and one box of vanilla, each yields one 13×9 size cake. To assemble – Chocolate cake on the bottom, a layer of strawberry mousse, then top with the vanilla cake. Frost with marshmallow frosting, pipe the roses on the top with a Wilton 2D tip (awesome tutorial here and here), brown with a culinary torch, and voila! You can certainly skip the rose decorations, the coolest part with the marshmallow frosting is that once torched, the cake will look awesome no matter how messy you frosted the cake. Keep the cake refrigerated until you are ready to serve.

birthday cake 1

Strawberry Mousse


1 envelope of unflavored gelatin
1/4 cup cold water
1 lb strawberry, hulled and sliced
1 Tbsp Grand Marnier or Cointreau (Optional)
1/2 cup caster sugar or confectioners’ sugar
1 1/4 cup whipping cream


1. In a heatproof bowl, sprinkle the gelatin to the cold water, let stand for 5 minutes to bloom.

2. In the mean time, reserve 5-6 strawberries and cut them in smaller chunks. In a food processor or blender, puree the remaining strawberries with sugar (and the optional alcohol).

2. Whip the heavy cream until stiff peaks formed.

3. Gently fold the whipped cream together with the pureed strawberry.

4. Over a double boiler, gently heat the gelatin until all the granules have dissolved. Add the gelatin and fold in the reserved strawberry chunks to the mousse and mix well.  Refrigerate the mousse 30 minutes to an hour until the mixture is thick and can hold its shape.

birthday cake 2

all piped and about to let Joe have some fun with the culinary torch.

Birthday cake 3

wheee! This was too cool!

Marshmallow Frosting

from Martha Stewart


  • 8 large egg whites
  • 2 cups sugar
  • 1/2 teaspoon cream of tartar
  • 2 teaspoons pure vanilla extract


  1. Place egg whites, sugar, and cream of tartar in the heatproof bowl of an electric mixer. Set over a saucepan with simmering water. Whisk constantly until sugar is dissolved and whites are warm to the touch, 3 to 4 minutes.
  2. Transfer bowl to electric mixer fitted with the whisk attachment, and beat, starting on low speed, gradually increasing to high, until stiff, glossy peaks form, 5 to 7 minutes. Add vanilla, and mix until combined. Use immediately.

Birthday cake 4

Birthday Cake 6

I can’t get over how gorgeous and simple this was, surely an elegant and easy way to class up any cake. If you don’t have a torch, just use your favorite buttercream recipe and you can still pipe out the roses.

What do you do with all those leftover egg yolks? I made this decadent chocolate espresso pots de creme with 6 of the yolks. Nom nom nom!


10 thoughts on “Neapolitan Birthday Cake with Marshmallow Frosting [recipe]

  1. OMGorgeous! Where did you get your propane? I confess – I’ve had a culinary torch for years, but I never used it. Never bought the butane. 😛 Love that you made pots de creme, too. Way to go, Joe, for lending a hand!

  2. I am in the process of making this cake for a friend’s birthday! Can’t wait to see how it turns out – going out and buying my torch today 🙂 Anyways, keep up the good work, love looking at your site to get inspired and try new things.

      1. Hi there – and sorry too for the late feedback from me! It turned out great! I made the chocolate and vanilla cake layers – but I did make my own strawberry buttercream for the filling. I went out and bought a torch-LOVE IT- and the recipe for the Marshmallow Frosting is THE BEST!!! I have tried another recipe for the marshmallow frosting before and it turned out terrible-but this one is GOLD! This is such a great idea for a cake and can be made for so many occasions! It is truly one one of my favorites to make! Thank you!!!

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