This post may contain affiliate links.
White Chocolate Mousse Cake is the kind of dessert that makes a room go quiet, a tender vanilla cake layered with silky butterscotch mousse, fluffy white chocolate mousse, and a glossy butterscotch drip, and it is the cake my family requests for every birthday now. I made the first one for a special celebration dinner and there was not a crumb left. If you love our strawberry earthquake cake, this layered mousse cake is the elegant, dinner party worthy showstopper.
It takes a little patience with the chilling, but every gorgeous layer comes together with simple steps and no special skills.
White Chocolate Mousse Cake Quick Look
- 🕒 Prep Time: 1 hour
- 🌡️ Cook Time: 30 minutes
- ⏳ Total Time: 5 hours
- 🍽️ Serving: 12 servings
- ⚡ Calories: 931kcal
- 🌶️ Flavor Profile: Tender cake with silky butterscotch and white chocolate mousse and a buttery toffee crunch
- ✋ Difficulty: Intermediate, an impressive step up from our banana bars
Quick Answer
Bake and cool a vanilla butterscotch cake layer in a springform pan. Make a butterscotch mousse with melted butterscotch chips, gelatin, and whipped cream, spread it over the cake, and chill. Repeat with a white chocolate mousse layer and chill again. Top with whipped cream, a butterscotch drizzle, and toffee bits, then release the springform and slice.
Jump to:
- White Chocolate Mousse Cake Quick Look
- Quick Answer
- Why This Recipe Works
- Why You’ll Love This Recipe
- Key Ingredients
- Variations and Substitutions
- How to Make White Chocolate Mousse Cake
- Recipe Tips & Tricks
- Serving Ideas and Suggestions
- White Chocolate Mousse Cake FAQs
- Other Recommended Showstopping Cake Recipes
- White Chocolate Mousse Cake with Butterscotch
Why This Recipe Works
Click to see the technique science
- A springform pan builds clean layers. Assembling the cake and mousse layers right in a springform pan means each layer sets up flat and even, so you get those gorgeous defined stripes when you slice.
- Gelatin sets the mousse. A little bloomed gelatin gives both mousses enough structure to hold a tall, sliceable layer while staying light and creamy.
- Two mousses for contrast. The rich, caramel like butterscotch mousse and the sweet, creamy white chocolate mousse balance each other for a dessert that is decadent but never one note.
- Toffee bits add crunch. Folding toffee into the cake and sprinkling it on top adds a buttery, crunchy contrast to all those silky smooth layers.
- Chilling makes it foolproof. Chilling between layers lets each one firm up before the next goes on, which is the secret to a tall, clean, professional looking cake.
Why You’ll Love This Recipe
- It is a true showstopper that looks like it came from a fancy bakery.
- Every slice has tender cake, two silky mousse layers, and a buttery toffee crunch.
- It is the perfect celebration dessert, even more impressive than our strawberry earthquake cake.
Key Ingredients
This cake has a few components, but the ingredient list is simple and the results are stunning.
- White chocolate chips: Melted into the cream for the light, sweet white chocolate mousse layer.
- Butterscotch chips: The base of the rich, caramel like butterscotch mousse layer.
- Heavy cream: Whipped and folded into both mousses to keep them light, fluffy, and sliceable.
- Toffee bits: Folded into the cake and sprinkled on top for a buttery, crunchy contrast.
- Gelatin: Bloomed and stirred in to give each mousse layer just enough structure to hold its shape.
See recipe card for exact quantities.
Variations and Substitutions
This cake is impressive as is, but here are a few ways to make it your own.
- Use milk or dark chocolate chips in place of white for a richer second mousse layer.
- Add a layer of caramel sauce between the cake and mousse for extra indulgence.
- Top with chopped pecans or a sprinkle of flaky salt along with the toffee bits.
- Make it a smaller, taller cake in a 6 inch springform for a real bakery look, the way we layer our strawberry earthquake cake.
How to Make White Chocolate Mousse Cake
- Make and bake the vanilla butterscotch cake layer in a springform pan, then let it cool completely.
- Make the butterscotch mousse by melting butterscotch chips with cream and bloomed gelatin, cooling, then folding in whipped cream.
- Make the white chocolate mousse the same way, melting white chocolate with cream and gelatin, then folding in whipped cream.
- Spread the butterscotch mousse over the cooled cake and chill, then add the white chocolate mousse layer and chill again until set.
- Whip the topping cream until fluffy and pipe a border around the top of the chilled cake.
- Drizzle warm butterscotch over the top, sprinkle with toffee bits, then release the springform, slice, and serve.
Recipe Tips & Tricks
- Use a springform pan so you can build the layers in the pan and release the cake cleanly when it is set.
- Bloom the gelatin properly in cold water before warming it, so it dissolves smoothly with no lumps in the mousse.
- Chill between every layer so each one firms up before the next goes on, giving you clean, defined stripes.
- Let the melted chocolate mixtures cool before folding in the whipped cream, or the cream will deflate.
- Use a warm knife wiped clean between cuts to slice through the layers neatly.
- Make it ahead. This cake needs hours to chill, so it is perfect to assemble a day before serving.
Serving Ideas and Suggestions
This white chocolate mousse cake is a true celebration centerpiece. Serve thin slices, since it is rich, and let everyone admire those gorgeous layers before they dig in.
It pairs beautifully with a cup of coffee or a glass of dessert wine. For a special occasion spread, set it out as the showstopper next to smaller treats like our banana bars and a plate of red velvet cookies.
Because it needs hours to set, this cake is ideal to make the day before. Keep it chilled, add the toffee and drizzle close to serving, and it will look and taste freshly made.
White Chocolate Mousse Cake FAQs
Yes, and you should. This cake needs several hours to chill and set, so it is perfect to assemble a day ahead. Add the whipped topping, butterscotch drizzle, and toffee close to serving.
The most common cause is gelatin that was not bloomed or dissolved properly. Bloom it in cold water first, then warm gently until fully dissolved before stirring it into the chocolate mixture.
A springform pan makes this cake much easier because you build and chill the layers right in the pan, then release the sides for clean, tall slices. It is the best tool for this recipe.
Make sure the cake is fully chilled and set, then slice with a sharp knife warmed under hot water and wiped clean between each cut. This glides through the mousse layers neatly.
You can freeze the assembled cake without the whipped topping and drizzle. Wrap it well, freeze, then thaw in the fridge and finish with the topping and butterscotch before serving.
Stored covered in the refrigerator, this cake keeps for up to 3 days. The layers stay creamy and the cake stays moist, making leftovers a real treat.
Made this white chocolate mousse cake? I would love to see your layers, leave a comment and a star rating below and tell me what you celebrated with it!
White Chocolate Mousse Cake with Butterscotch
Ingredients
For the Cake
- ¼ cup salted butter room temperature
- ¼ cup canola oil
- ¾ cup granulated sugar
- 2 large eggs
- 1 & ½ teaspoon vanilla extract
- ½ cup cream
- 1 & ¼ cup all-purpose flour
- 2 tablespoons cornstarch
- 1 & ½ teaspoons baking powder
- ¼ teaspoon salt
- ½ cup butterscotch topping syrup
- ¾ cup toffee bits divided ½ cup and ¼ cup
For the Butterscotch Mousse
- 1 & ½ cups heavy whipping cream
- 9 ounces butterscotch chips
- 2 tablespoons salted butter
- 2 tablespoons water
- 2 teaspoons gelatin powder unflavored
- ⅛ teaspoon salt
For the White Chocolate Mousse
- 1 & ½ cups heavy whipping cream
- 9 ounces white chocolate chips
- 2 tablespoons salted butter
- 2 tablespoons water
- 2 teaspoons gelatin powder unflavored
For the Butterscotch Ganache Drip
- ½ cup butterscotch chips
- 2 tablespoons heavy cream
For the Whipped Cream
- 1 cup heavy cream
- 2 tablespoons granulated sugar
Instructions
For the Cake
- Preheat the oven to 350°F and prepare an 8” or 9” round cake pan by spraying the bottom and sides with cooking spray and lining the bottom with parchment paper, and set aside.
- In a large bowl, mix the butter, sugar, oil, eggs, and vanilla in a large bowl with an electric hand mixer on medium speed. Beat until the mixture becomes lighter in color and airy in texture, 3 minutes.
- Add the heavy cream, and mix to combine.
- Sift the dry ingredients: flour, cornstarch, baking powder, and salt into the mixture and mix until combined with no dry patches.
- Pour the cake batter into the prepared pan and bake in the oven for 25-30 minutes or until cooked through. Test the cake by inserting a toothpick into the center of the cake, if it comes out clean, the cake is done.
- Remove the cake from the oven and let it cool for 10 minutes on the counter, then run a knife around the outer edges and gently turn the cake out onto a serving plate. (Be sure to remove the parchment paper on the bottom.)
- Carefully use a long serrated knife to level the top of the cake by cutting off any dome or rounded top of the cake.
- Pour ½ cup of butterscotch topping syrup over the top of the cake and use a pastry brush or spoon to spread the syrup evenly across the top.
- Cut off the outer edge of the golden brown cake and discard. This makes for a prettier presentation.
- Wrap the outer sides of the cake with an acetate cake collar (or similar).
- Sprinkle the top of the cake with an even generous layer of toffee bits, approximately ½ cup.
- Let the cake in the fridge until completely cool.
For the Butterscotch Mousse
- Once the cake is cool, make the butterscotch mousse by combining ¼ cup of the cream, butter, 9 oz of butterscotch chips, and salt in a small saucepan. Heat slowly over medium-low heat, constantly stirring, until the chips have melted. Set aside to cool.
- Once the butterscotch mixture has mostly cooled but is still fluid, place 2 tablespoons of cool water in a small microwave-safe dish. Sprinkle the gelatin powder over the top of the water and let rest.
- While the gelatin rests, whip 1 ¼ cups of the heavy whipping cream in a large mixing bowl to soft peaks with an electric mixer or in the bowl of a stand mixer with the whisk attachment.
- Once the gelatin absorbs the water, place it in the microwave for 3-5 seconds or until it becomes liquid, but is not hot.
- Gently stream the liquid gelatin mixture into the softly whipped cream while whipping at high speed. Continue to whip until you achieve stiff peaks.
- Fold the cooled butterscotch mixture into the whipped cream until combined, then pour it over the top of the cake inside of the cake collar.
- Use a spoon or spatula to smooth the top of the mousse. Set the cake back in the refrigerator while making the white chocolate mousse.
For the White Chocolate Mousse
- Combine ¼ cup of the cream, butter, and 9 oz of white chocolate chips in a small saucepan. Heat slowly over medium low heat, constantly stirring, until the chips have melted. Set aside to cool.
- Once the white chocolate mixture has mostly cooled but is still fluid, place 2 tablespoons of cool water in a small microwave-safe dish. Sprinkle gelatin powder over the top of the water and let rest.
- While the gelatin rests, whip 1 ¼ cups of the heavy whipping cream to soft peaks with an electric hand mixer or in the body of a stand mixer with the whisk attachment.
- Once the gelatin absorbs the water, place it in the microwave for 3-5 seconds or until it becomes liquid, but is not hot.
- Gently stream the liquid gelatin into the softly whipped cream while whipping at high speed. Continue to whip until you achieve stiff peaks.
- Fold the cooled white chocolate mixture into the whipped cream until combined, then pour it over the top of the butterscotch mousse layer inside the cake collar.
- Use a spoon or spatula to smooth the top of the mousse, try to make it as smooth and even as possible. Cover the open top of the cake collar with plastic wrap and set the cake back into the refrigerator to set overnight.
For the Butterscotch Ganache
- After the cake has fully set, you can make the butterscotch ganache for the drip. Combine ½ cup of butterscotch chips in a microwave-safe bowl with 2 tablespoons of heavy cream.
- Heat in the microwave stirring every 15 seconds until the chips have melted and combined with the cream.
- Let the ganache cool until it is cool and thick yet still able to drip/pour. Transfer the ganache to a piping bag with a round open tip about the size of a pencil eraser. You can also use a zip-top bag and snip one of the bottom corners to make your own piping bag.
- Remove the cake collar from the cake.
- Working slowly and carefully, pipe the ganache around the very outer edge of the top of the cake, allowing the ganache to drip down the sides, alternating between long, short, and medium-length drips. Leave the center of the cake plain, no need to fill the top center with the ganache unless you wish to do so or have extra ganache.
- Sprinkle the remaining ¼ cup of toffee bits on the top center of the cake inside the ganache ring.
For the Whipped Cream
- Before you are ready to serve, make the whipped cream for the final decor. In a bowl, whip 1 cup of heavy cream with 2 tablespoons of sugar until you reach stiff peaks with an electric hand mixer.
- Transfer the whipped cream into a piping bag fitted with a large open star tip.
- Pipe swirls of whipped cream along the top outer edge of the cake. Pipe stars of whipped cream along the bottom edge of the cake. Store in the fridge until ready to serve, then slice and serve with more whipped cream, toffee bits, or butterscotch syrup if desired.
Notes
- This makes a large cake, but you can easily double it to feed more and make two cakes at the same time.
- If you don’t have or don’t want to use the cake collar, this can be made in a trifle dish or in individual portions, see more info above.
- Great for a make-ahead dessert since it needs to set up overnight.
- This freezes well, see my tips above on how to store.
- Skip the butterscotch drip if not desired.
Nutrition
Love This Recipe?
Follow @ThisSillyGirlsKitchen on Instagram and @danadevolk on Pinterest for more!
