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High-angle close-up of Chocolate Mousse Cake Filling between dark sponge layers with a ganache drip.

Chocolate Mousse Cake Filling: The Ultimate Stable & Silky Recipe

A professional-grade Chocolate Mousse Cake Filling that is perfectly aerated yet stable enough for multi-layer cakes. Featuring a rich matte finish, dark chocolate sponge, and a glossy ganache drip.
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Prep Time 45 minutes
Cook Time 35 minutes
Total Time 1 hour 20 minutes
Servings: 12 slices
Course: Desserts
Cuisine: American
Calories: 520
Ingredients Equipment Method Notes

Ingredients
  

Dark Chocolate Sponge
  • 2 cups All-purpose flour 250g
  • 1 cup Dutch-process cocoa powder 90g
  • 1 cup Buttermilk 240ml
  • 1 cup Hot coffee 240ml
Stable Mousse Filling
  • 8 oz Dark chocolate 225g, 60% cocoa
  • 2 cups Heavy whipping cream 480ml, chilled
  • 1 tsp Unflavored gelatin 5g
  • 1/2 cup Powdered sugar 60g
Garnish
  • 3 whole Fresh blackberries Glossy and plump
  • 1/4 cup Chocolate shavings Hand-curled

Equipment

  • 3 8-inch Cake Pans Lined with parchment paper
  • 1 Stand Mixer With whisk attachment
  • 1 Rubber Spatula For gentle folding

Method
 

Bake the Sponge
  1. Whisk dry ingredients; add buttermilk, eggs, and oil. Stir in hot coffee last to bloom the cocoa.
  2. Divide into three pans and bake at 350°F (175°C) for 30-35 mins. Cool completely.
Make the Mousse Filling
  1. Melt dark chocolate. Bloom gelatin in water, then melt. Let both cool to room temp.
  2. Whip cream, cocoa, and sugar to soft peaks. Fold in melted chocolate and gelatin until a matte light brown hue is achieved.
Assemble & Decorate
  1. Stack cake layers with thick mousse in between. Chill for 4 hours.
  2. Apply ganache drip, chocolate curls, and 3 blackberries on top.

Notes

Always use chilled heavy cream for maximum volume.
Allow the melted chocolate to cool to 85°F to prevent the mousse from deflating.