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Royal Chocolate Cake - Trianon

Sliced Royal chocolate cake on a golden cake board with crepes Gravottes on background

5 from 16 reviews

Here is a recipe for Royal cake - French dark chocolate mousse cake, also called Trianon - that consists of nut dacquoise, crispy layer of crepes Gavottes, and chocolate mousse. Just make it and enjoy the best chocolate goodness ever.

Ingredients

Scale

For the dacquoise:

For the crunchy praline feuillantine:

  • 1.7 oz (50 g) crepes Gravottes
  • 1.7 oz (50 g) milk chocolate
  • 1.7 oz (50 g) hazelnut spread Nutella
  • 1.7 oz (50 g) Hazelnut Praline Paste

For the chocolate mousse:

  • 2 cup + 3 tablespoons (500 ml) whipping cream
  • 5 tablespoons (75 g) whole milk
  • 7 oz (200 g) dark chocolate 

For the cocoa mirror glaze:

  • 2/3 cup + 4 1/2 tablespoons (210 g) granulated sugar
  • 5 tablespoons (75 g) water
  • 9 1/2 tablespoons (70 g) cocoa powder, unsweetened
  • 1/2 cup + 2 tablespoons (145 ml) whipping cream
  • 3 1/3 gelatin sheets (8 g powdered gelatin - see note #2)

*Don't you have the correct baking pan on hand right now? Try this simple Cake Pan Converter!

Instructions

  1. To make the dacquoise, preheat oven to 335 F/170 C. Using a flour sifter, sift powdered (icing) sugar, almond, and hazelnut flour. In a separate bowl, whisk egg whites and gradually add granulated sugar until slightly firm. Once the meringue is ready, add icing sugar/flour mixture and gently mix with a spatula.
  2. Transfer the preparation in a pastry bag with Ateco plain pastry tip 809. Adjust a mousse cake mold to 7 inches/18 cm in diameter. Pipe a spiral inside the mold placed on a baking sheet with the parchment paper or simply use a spoon. Bake for 20 to 25 minutes. Let it cool in a frame. 
  3. To make the crunchy praline feuillantine,  crush crepes Gravottes roughly with hands or a rolling pin. Melt milk chocolate in a bain-marie/water bath. In a bowl, place hazelnut praline, Nutella and crepes' chips and mix. Add melted chocolate and mix again.
  4. Use a knife to loosen the dacquoise from the mold, but keep it inside. Pour the crunchy mixture over dacquoise, spread it on a thin layer. Then remove the mold and freeze the dacquoise for about 10 to 15 minutes. 
  5. To make the chocolate mousse, whip the cold whipping cream in a bowl to get the whipped cream and refrigerate.  Melt dark chocolate broken in small pieces in a bain-marie/water bath. Bring milk to a boil, pour it over the melted chocolate, and mix with a rubber spatula until smooth. When the chocolate mixture is lukewarm, add it to the whipped cream and mix with a spatula as fast as possible. Transfer the mousse in a pastry bag with a plain tip.
  6. To assemble the cake, seal one side of an 8 inches/20 cm cake ring with a plastic film and place it on a wooden board or a baking sheet. Insert an acetate collar inside the ring. Poach the chocolate mousse in the trying to raise on the sides of the ring. Take the dacquoise disk from the freezer, turn it over and place it over the mousse (dacquoise side up). Slightly press the disk and remove the excess mousse with a bent spatula. Cover with a plastic film and freeze for at least 5 hours.
  7. To make the cocoa mirror glaze, soak gelatin sheets in cold water for 10 minutes. Heat whipping cream over low heat and set aside. Pour water and sugar in a saucepan and bring to a boil. Once the sugar syrup starts boing actively, pout it over the sifted cocoa powder and gently mix, trying not to incorporate air. Add the drained gelatin and mix it with a hand blender. Then pout hot whipping cream and mix again. Pass the mixture through a fine-mesh sieve and mix with a hand blender. Let the glaze cool down to 86 F/30 C.
  8. To glaze the cake, take the dessert out of the freezer. Place the cake on a wire rack or a plate, which is itself placed on a baking sheet to collect the excess glaze. Remove the plastic film, mold (heat the sides of the ring with a blow torch), and acetate collar. Pour the glaze over the cake and remove the excess glaze with a bent spatula, passing it over the top once. Transfer the dessert on a cake board with the use of two metal spatulas. Place the cake in the fridge to thaw for 3 to 4 hours.

Notes

  1. 55 g egg whites approximately equal 1 1/2 raw fresh egg whites from extra large size chicken eggs.
  2. To substitute sheet gelatin, use 8 g of powdered gelatin and 1/4 cup (60ml) of cold water.
  3. Do not over whisk egg whites while making the dacquoise. They have to be slightly firm to incorporate the nut flour.
  4. Spread the chocolate mousse well inside the mold, using a rubber spatula to avoid trapping air in the cake.
  5. Once the cocoa mirror glaze is applied, use a bent metal spatula to remove the excess with a single pass over the top of the cake to avoid making marks.
  6. Store the decorated cake for 2 to 3 days in the fridge.
  7. Take the dessert out of the fridge about 20 minutes before tasting (the cold temperature alters the taste of chocolate).

Nutrition

Keywords: Cake Royal, Royal cake, Royal chocolate cake recipe, cake Trianon, dark chocolate mousse cake

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