👨‍🍳 步驟

1. 1

   Prepare the Joconde Sponge: Preheat oven to 200°C (400°F). Line a baking sheet (approx. 40x30 cm or 16x12 inches) with parchment paper. In a large bowl, whisk together almond flour, powdered sugar, and whole eggs until smooth. In a separate bowl, whisk egg whites with cream of tartar until soft peaks form. Gradually add a portion of the powdered sugar and beat until stiff, glossy peaks form. Gently fold about one-third of the meringue into the almond mixture to lighten it, then fold in the remaining meringue and the sifted all-purpose flour until just combined, being careful not to deflate the batter. Spread the batter evenly onto the prepared baking sheet. Bake for 8-10 minutes, or until the sponge is lightly golden and springs back when gently touched. Let cool completely on a wire rack.

   ⏱️ 30 minutes (prep) + 10 minutes (bake)
2. 2

   Make the Coffee Syrup: In a small saucepan, combine water, granulated sugar, and 1 tbsp of instant espresso powder. Heat gently, stirring until the sugar dissolves. Bring to a simmer for 1 minute, then remove from heat and let cool.

   ⏱️ 5 minutes
3. 3

   Make the Coffee Buttercream (Italian Meringue Buttercream): Whisk 2 egg yolks with 1 tbsp of espresso powder. In a small saucepan, heat 50ml water and 50g sugar to 118°C (245°F). While the syrup is heating, whisk the remaining egg whites (from the 6 total eggs) with cream of tartar until soft peaks form. Slowly pour the hot sugar syrup in a thin stream into the whisking egg whites, continuing to whisk until the meringue is stiff and glossy and the bowl is cool to the touch. In a separate bowl, cream the softened butter until smooth and pale. Gradually beat the cooled meringue into the butter, a spoonful at a time, until fully incorporated and the buttercream is light and fluffy. Beat in the egg yolk and espresso mixture until well combined.

   ⏱️ 30 minutes
4. 4

   Make the Chocolate Ganache: Finely chop the dark chocolate and place it in a heatproof bowl. Heat the heavy cream (100ml) with 1 tbsp of espresso powder in a small saucepan until just simmering. Pour the hot cream over the chocolate and let it sit for 1 minute, then whisk gently until smooth and glossy. Let cool slightly.

   ⏱️ 10 minutes
5. 5

   Assemble the Cake: Trim the cooled Joconde sponge to fit your desired cake pan (e.g., 20x20 cm or 8x8 inches). Cut the sponge into two equal layers. Place one layer in the bottom of the pan. Brush generously with half of the coffee syrup. Spread half of the coffee buttercream evenly over the syrup. Top with the second layer of Joconde sponge and brush with the remaining coffee syrup. Spread the chocolate ganache evenly over the syrup. Chill the cake for at least 1 hour, or until the ganache is firm.

   ⏱️ 45 minutes (assembly) + 1 hour (chilling)
6. 6

   Prepare the Chocolate Glaze and Finish: Gently heat the remaining 100ml heavy cream with the remaining 1 tbsp espresso powder until just simmering. Pour over the remaining 200g chopped dark chocolate in a heatproof bowl. Let sit for 1 minute, then whisk until smooth. Let the glaze cool to about 30°C (86°F) – it should be pourable but not too hot. Remove the chilled cake from the pan and place it on a wire rack set over a baking sheet. Pour the chocolate glaze evenly over the top and sides of the cake, ensuring a smooth, even coating. Allow excess glaze to drip off. If desired, use edible gold leaf or dust to write 'Opéra' on top. Chill the cake for at least 4-5 hours, or preferably overnight, to allow the layers to meld and set completely.

   ⏱️ 15 minutes (glaze) + 4-5 hours (chilling)