Equipment
Ingredients
Chocolate Buttercream
- 115 g unsalted butter, softened at room temperature
- 100 g granulated sugar
- 1 egg, room temperature
- 85 g bittersweet chocolate, melted and cooled to room temperature
Soaking Liquid
- 120 ml espresso, hot
- 15 g granulated sugar
Assembly
- 64 biscuits
- 10 g dark chocolate, solid
Nutrition (per serving)
Method
In a small mixing bowl, cream the softened butter until it is smooth and aerated.
Add 100g of granulated sugar to the butter and beat until fully incorporated.
In a separate clean bowl, whip the egg white until it reaches soft peaks.
Lightly whisk the egg yolk in a small cup, then gently stir it into the whipped egg white.
Fold the egg mixture into the butter and sugar mixture until the two are completely combined.
Stir the melted and cooled bittersweet chocolate into the buttercream until the mixture is uniform in color.
Combine the hot espresso and 15g of sugar in a wide, shallow bowl, stirring until the sugar dissolves.
Quickly dip each biscuit into the espresso mixture for 3 seconds per side.
Arrange the soaked biscuits on a serving plate to form the base layer of the cake.
Spread one-quarter of the chocolate buttercream evenly over the biscuit layer using an offset spatula.
Repeat the soaking and spreading process three more times to create a total of four layers, ending with buttercream on top.
Grate the solid chocolate over the final layer of buttercream for decoration.
Refrigerate the cake at 4°C (40°F) for at least 3 hours to allow the frosting to set and the biscuits to soften.
Chef's Notes
- Ensure your butter is truly softened but not melted for the smoothest buttercream. Overly soft butter can lead to a greasy texture.
- When dipping the biscuits, work quickly and in batches. The espresso mixture should be warm, not hot, to avoid dissolving the biscuits too much.
- For a more intense chocolate flavor, consider using a higher percentage of cacao in your bittersweet chocolate, around 70%.
- Allowing the cake to chill for the full duration is crucial. This allows the biscuits to absorb moisture from the buttercream, creating a tender, cake-like consistency.
- If you don't have espresso, strong brewed coffee can be substituted, though it will alter the flavor profile slightly.
Storage
Refrigerator: 3 days — Store in an airtight container to prevent the buttercream from absorbing refrigerator odors.
Freezer: 1 month — Wrap tightly in plastic wrap and foil.
