We’ve always loved vanilla cake with chocolate icing. The chocolate icing with buttery vanilla layers is the ultimate combination. This cake takes our childhood favorite birthday cake and turns it into something truly delicious. It’s three fluffy vanilla cake layers, two dark chocolate mousse layers, and a generous layer of chocolate ganache.
This is the cake we make when we to go all out for a birthday, holiday, or just because Tuesday needs a little something. Although we love this vanilla cake on its own, the addition of the chocolate adds the ultimate twist.
Why You’ll Love This Recipe
- Bakery-worthy at home: Each step is simple but builds to something beautiful.
- Light but rich: The chocolate mousse brings depth without heaviness.
- Make-ahead friendly: The mousse sets in the fridge overnight.
- That classic flavor combo: Vanilla cake + chocolate frosting = forever favorite.
Vanilla Cake with Chocolate Mousse Filling
Servings 12
Ingredients
- 3 vanilla cake layers linked below
Chocolate Mousse:
- 14 ounces chopped dark chocolate 70% cocoa 400 g
- 2 tablespoons Salted European Style Butter 28 g
- ¼ cup Kahlua 60 ml ¼ cup brewed coffee
- 1 Tablespoon vanilla bean paste
- ½ teaspoon salt
- 3 large eggs separated
- ¼ cup granulated sugar 50 g
- 1 teaspoon unflavored gelatin 5 ml
- 3 tablespoons water 45 ml
- 1 ½ cups Heavy Whipping Cream 360 ml divided
Ganache:
- 8 ounces dark chocolate 70%
- 6 tablespoons butter 85 g
- 1 ¼ cup sugar 250 g
- 1 ¼ cup heavy cream 300 ml
- 2 teaspoons vanilla 10 ml
- Pinch of salt
Instructions
Chocolate Mousse:
- Line 2 8” cake pans with plastic wrap and set aside. Note the mousse is going to be divided into two and poured into the pans so make sure the plastic is large enough to cover the full base and up the edges.
- Add the chopped dark chocolate, butter, and Kahlua into a bowl. In a double boiler over medium heat, melt together the mixture. (This can also be done in a microwave in 30-second intervals). Mix in the salt and vanilla and set aside to cool slightly.
- In a stand mixer or with a hand mixer, add the egg whites and whisk together on medium speed until just foamy. After the egg whites are foamy, add in the sugar and whip until medium peaks form.
- Add the gelatin to the water. Mix to combine and set aside to bloom for at least 5 minutes.
- While the gelatin is blooming, whip the egg yolks in a bowl with a hand mixer or the base of a stand mixer until they are pale in color. Fold the whipped egg yolks into the chocolate mixture.
- After the yolks are added, heat ½ cup of heavy cream in the microwave until warm but not boiling. Add the gelatin-water mixture to the warmed cream and mix to combine. Fold the mixture into the chocolate mixture.
- After the gelatin is added, fold the whipped egg whites into the chocolate mixture
- Lastly, whip the remaining 1 cup of heavy whipping cream until soft peaks form. Fold the whipped cream into the chocolate mixture until combined.
- Pour the mousse in the two prepared plastic lined cake pans, pouring half in each. Spread into an even layer so the top is flat. Set for at least 4 hours in the fridge or overnight
- When it has been at least 4 hours and it is time to bake the cake layers, remove from the cake pans (we like to lift it with the plastic wrap and place it plastic side down on a plate) and place the mousse layers back in the fridge until assembly time
Ganache:
- To make the ganache, add chocolate, butter, salt, and vanilla into a bowl. Set aside.
- In a small pan over medium heat, heat cream and sugar until hot but just before boiling.
- Pour the heated cream and sugar over the bowl of chocolate and let it set for 1 minute.
- Stir until smooth and set in the fridge until cool but not hard.
Assembly:
- When all components are ready, start by placing a vanilla cake layer on your plate or cake stand. Then place a piece of the set mousse on top (we like to flip it so the mousse is touching the cake layer and the plastic wrap side is facing up. We then slowly peel off the plastic wrap). Repeat this another time and place the final cake layer on top
- After the cake is stacked, we gently go around the mousse layer with a spoon to carve out a slight indent. It should be about a half inch deep (This will get filled with icing and keeps the mousse inside the cake)
- After creating the indent, ice the cake with the chocolate ganache. Serve immediately or store in the fridge until ready to serve
Notes
Use our favorite vanilla cake recipe and bake it into three 9-inch layers (note that the recipe is written for 8 but we recommend 9″ given how high this cake is! Either way will work just know with 8″ it is quite a tall cake!).
Steps:
1. Make the Chocolate Mousse
- Line two 8” cake pans with plastic wrap. Set aside.
- Melt chocolate, butter, and Kahlua in a double boiler (or microwave in 30-second bursts). Stir in vanilla and salt. Let cool slightly.
- Beat egg whites until foamy, then slowly add sugar. Whip to medium peaks.
- Bloom gelatin in water (let sit at least 5 minutes).
- Whip egg yolks until pale. Fold into chocolate mixture.
- Warm ½ cup of cream, then stir in bloomed gelatin until dissolved. Fold into chocolate mixture.
- Gently fold in the whipped egg whites.
- Whip remaining 1 cup cream to soft peaks. Fold into chocolate mixture.
- Divide mousse into lined pans and spread evenly. Chill 4+ hours or overnight.
2. Make the Ganache
- Place chocolate, butter, vanilla, and salt in a bowl.
- In a saucepan, heat cream and sugar until hot (just before boiling).
- Pour cream over chocolate and let sit for 1 minute. Stir until smooth.
- Chill until cool and spreadable but not solid.
3. Assemble the Cake
- Place a vanilla cake layer on a plate or stand.
- Top with a mousse layer (flip so the mousse touches cake, then peel off plastic).
- Repeat with the second cake and mousse layers, ending with the final cake layer.
- Gently carve a shallow ½-inch trench around the mousse to help seal it in.
- Frost the whole cake with ganache.
- Refrigerate until ready to serve. Slice with a hot, clean knife for perfect layers.
Tips for Success
- Give it time: The mousse layers need at least 2 hours to set. This is a very tall cake and if they don’t sit for enough time, the cake won’t stay up.
- Don’t skip the gelatin: It helps the mousse hold shape for clean slices. Again, the cake is tall so without this, the cake just won’t hold.
- Use quality chocolate: Since the chocolate is the primary flavor, it is important to use quality chocolate in both the mousse and ganache.
- Level your cake layers: A flat surface makes sure the final cake is not a leaning tower of pisa.
Frequently Asked Questions
Can I make it ahead?
Yes! The mousse and ganache can be made a day in advance. The assembled cake keeps well in the fridge for up to 24 hours.
What can I substitute for Kahlua?
Brewed coffee works great. You could also use espresso or hot water with a splash of vanilla extract.
Do I need to use a mixer?
A hand or stand mixer is very helpful for the mousse. You’ll need it to whip the eggs and cream properly.
Can I use store-bought cake layers?
You can, but we highly recommend making our homemade vanilla cake, we promise it’s worth it.
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