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Chocolate Mousse Cake

Hide&Seek Chocolate Mousse Cake

Rich and creamy milk chocolate mousse with a delicious chocolate cake base, topped with crispy, crunchy Hide&Seek biscuits - this mousse cake is the perfect dessert when you want to impress a crowd with very little effort.
Servings 8 servings
Prep Time 1 hour
Cook Time 20 minutes
Chill Time 6 hours
Total Time 7 hours 20 minutes
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Equipment

  • 8x8" pastry frame or serving dish to set trifle-style
  • Hand whisk
  • Silicone spatula
  • Offset spatula

Ingredients
  

Chocolate Cake

  • 120 grams all-purpose flour
  • 40 grams cocoa powder
  • 1/2 tsp instant coffee powder
  • 1 tsp baking powder
  • 3/4th tsp baking powder
  • 1/2 tsp salt
  • 100 grams granulated white sugar
  • 100 grams packed brown sugar substitute with more white sugar
  • 125 ml buttermilk substitute with milk mixed with vinegar
  • 60 ml neutral oil
  • 1 egg
  • 1 tsp vanilla extract
  • 125 ml boiling water

Chocolate Mousse

  • 5 grams gelatin powder
  • 25 ml ice-cold water for blooming gelatin
  • 70 ml liquid whipping cream/heavy cream for boiling
  • 70 ml full-fat milk
  • 200 grams milk chocolate
  • 225 ml whipping cream for whipping
  • 200 grams Hide&Seek biscuits or any other chocolate chip cookies of your choice

Instructions
 

Chocolate Cake

  • Combine the flour, cocoa powder, coffee powder, baking powder, baking soda, and salt in a mixing bowl.
  • Add in the brown sugar, granulated sugar, buttermilk, egg, oil, and vanilla. Whisk until you have a smooth batter.
  • Slowly pour in the hot water and whisk until fully incorporated.
  • Transfer the batter to the prepared cake pan and bake for 20–25 minutes, or until a skewer inserted into the centre comes out clean. Allow the cake to cool completely, then move it to your serving or assembly dish.

Chocolate Mousse

  • Soak the gelatin in cold water and refrigerate for about 15 minutes until bloomed.
  • Heat the milk and cream together in a saucepan just until small bubbles form around the edges. Do not let it boil.
  • Place the chopped chocolate in a heat-safe bowl and pour the hot cream mixture over it. Let it stand for 2 minutes, then whisk until smooth and glossy.
  • While the ganache is still warm, add the bloomed gelatin and whisk until fully dissolved. If the mixture has cooled too much, the gelatine won’t incorporate properly. Set the ganache aside to cool to room temperature.
  • In another bowl, whip the cream to medium peaks. Be careful not to overwhip, as this can cause the cream to split later.
  • Once the ganache has cooled, gently fold it into the whipped cream using a silicone spatula until smooth and evenly combined.
  • Spread the mousse evenly over the cooled chocolate cake layer. Refrigerate for 6-8 hours, or preferably overnight, until fully set.
  • Just before serving, top with Hide & Seek biscuits so they stay crisp. Serve chilled.

Notes

Storage:
This can be stored in an airtight container in the fridge for up to 3 days. The biscuits will soften over time, so place them just before serving. 
Tips & Tricks:
  • Let the cake cool completely before adding the mousse. A warm cake can melt the mousse and prevent it from setting properly.
  • Make sure the ganache is warm when adding gelatin. Gelatin only dissolves properly in a hot mixture, so add it before the ganache cools too much.
  • Whip the cream to medium peaks only. Overwhipped cream can split when folded with the ganache, affecting the mousse’s texture.
  • Always fold gently, not stir. Using a silicone spatula and light folding motions helps keep the mousse airy and smooth.
  • Chill for enough time. The mousse needs at least 6-8 hours in the fridge to set fully, but overnight chilling gives the cleanest slices.
  • Add the biscuits at the last moment. This keeps them crunchy and prevents them from softening in the fridge.