Description
A luxurious White Chocolate Mousse Cake featuring light and airy white cake layers filled with creamy white chocolate mousse and frosted with smooth white chocolate buttercream. Perfect for special occasions or indulgent dessert cravings, this cake combines rich textures and delicate sweetness with expert baking and assembly techniques.
Ingredients
Scale
White Chocolate Mousse
- 1 1/3 cups good quality white chocolate chips (215g)
- 1 1/2 cups heavy cream or heavy whipping cream, cold (360ml), divided
- 1/4 cup powdered sugar (30g)
- 1 tsp vanilla extract or vanilla bean paste (4ml)
- Pinch fine salt (less than 1/8 tsp)
White Cake
- 1 cup (2 sticks) unsalted butter, room temperature (226g)
- 3 cups granulated sugar (600g)
- 1 cup carton egg whites or 7 large egg whites, room temperature (235g)
- 3 cups cake flour (360g)
- 2 1/2 tsp baking powder (10g)
- 1 tsp fine salt (6g)
- 1 1/2 cups full-fat sour cream, room temperature (380g)
- 1/4 cup vegetable or canola oil (56 ml)
- 1 tsp vanilla extract or vanilla bean paste (4ml)
White Chocolate Buttercream Frosting
- 2 cups unsalted butter, room temperature (452g)
- 7 cups powdered sugar (900g)
- 1 tsp vanilla extract or vanilla bean paste (4ml)
- 1/2 tsp fine salt (3g)
- 1/3 cup heavy whipping cream, room temperature (75g)
- 1 cup white chocolate chips, melted and cooled (160g)
Instructions
- Make the White Chocolate Mousse: Combine white chocolate chips with 1/2 cup heavy cream in a heat-proof bowl. Microwave 60-75 seconds or use double boiler until melted and smooth. Let cool slightly. In a stand mixer bowl, whip 1 cup heavy cream, powdered sugar, vanilla, and salt until thick peaks form (about 2.5 to 3 minutes). Gently fold half the whipped cream into melted chocolate, then fold in remaining whipped cream without deflating. Cover and chill at least 2 hours or up to 2 days.
- Prepare White Cake Layers: Preheat oven to 325°F (163°C). Grease and line 4x 7-inch or 3x 8-inch pans. Beat butter and sugar on high speed until light and fluffy. Add egg whites and mix till combined. Whisk flour, baking powder, and salt separately. Add half dry ingredients to butter mixture, mix low speed. Add sour cream, oil, and vanilla and mix. Add remaining dry ingredients, mix until combined. Divide batter evenly using scale. Bake 37-40 minutes until toothpick comes out with moist crumbs. Cool 10 minutes and run spatula around edges. Freeze pans for 45 minutes for faster cooling. Remove cakes and level tops with serrated knife.
- Make White Chocolate Buttercream Frosting: Beat butter on low speed until smooth. Add vanilla and salt. Gradually add powdered sugar alternating with heavy cream. Fold in melted and cooled white chocolate. Adjust consistency with more cream or sugar as needed. Transfer to piping bag and seal with 3/4 inch opening.
- Assemble the Cake: Place first cake layer on greaseproof cake board using a dab of frosting to secure. Pipe buttercream ring on perimeter, fill center with white chocolate mousse (1/3 of mousse per layer if 4 layers, 1/2 if 3 layers). Repeat for remaining layers. Apply thin crumb coat of frosting all over cake, chill until firm. Add thick layer of frosting, smooth with icing comb. Decorate with piped buttercream swirls and sprinkles as desired. Chill before serving.
Notes
- Chill mixer bowl and whisk to speed up whipping cream for mousse.
- Measure flour properly, preferably with a kitchen scale for accurate results.
- Mix cake batter just until combined to maintain tenderness and fluffiness.
- Use a kitchen scale to evenly divide batter for uniform cake layers.
- Banging cake pans before baking helps release trapped air bubbles for even texture.
- Level cake layers when cool to ease stacking and frosted cake stability.
- Freeze cake layers before assembly to make them easier to handle.
- Make mousse, cake layers, and frosting ahead to break up the process and enhance flavor.
- Store leftover frosting in airtight container in fridge up to 1 month, or freezer up to 3 months. Stir well after thawing.
- Frosted cake keeps fresh in fridge up to one week or freezer up to one month.
- Use remaining frosting to cover cut edges of leftovers to maintain moisture.
Nutrition
- Serving Size: 1 slice (1/24th of cake)
- Calories: 460 kcal
- Sugar: 45 g
- Sodium: 130 mg
- Fat: 28 g
- Saturated Fat: 17 g
- Unsaturated Fat: 9 g
- Trans Fat: 0.5 g
- Carbohydrates: 50 g
- Fiber: 0.5 g
- Protein: 4 g
- Cholesterol: 95 mg
