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A slice of opera cake with "opera" written on top with a fork beside it.
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Opera Cake

Bursting with coffee flavors, this Opera Cake is a classic French dessert that any coffee lover will enjoy. Layers of almond cake with coffee buttercream, coffee syrup, and a chocolate ganache, this dessert is rich and decadent.
Course Dessert
Cuisine French
Prep Time 2 hours
Cook Time 10 minutes
Total Time 2 hours 10 minutes
Servings 10 servings
Calories 670kcal
Author John Kanell

Equipment

  • Electric or stand mixer
  • Large jelly roll pan
  • Parchment paper
  • Saucepan
  • Mixing Bowls
  • Piping bag

Ingredients

For the Almond Sponge Cake:

  • 4 large eggs
  • 1 ¼ cups almond flour (125g)
  • ¾ cup powdered sugar (90g)
  • ¼ cup all-purpose flour (30g)
  • 3 egg whites
  • 2 tablespoons granulated sugar
  • 3 tablespoons unsalted butter melted

For the Coffee Syrup:

  • ¼ cup granulated sugar (50g)
  • 2 teaspoons instant espresso powder
  • ¼ cup water (60ml)
  • ¼ cup brandy or cognac

For the Chocolate Glaze:

  • 8 ounces semi-sweet chocolate finely chopped (225g)
  • 7 tablespoons unsalted butter cubed (100g)

For the Coffee Buttercream:

  • 2 teaspoons instant espresso powder
  • 4 tablespoons hot water divided (60ml)
  • ½ cup plus 2 tablespoons granulated sugar (125g)
  • 6 egg yolks
  • 1 cup unsalted butter softened (227g)

Instructions

For the Almond Sponge Cake:

  • Preheat the oven to 425F. Butter a 17x11-inch jelly roll pan or rimmed baking sheet. Line with parchment paper and butter again and lightly flour.
  • In a large mixing bowl, beat the eggs on medium-high speed until foamy. Add the almond flour and sift in the confectioners’ sugar. Beat until pale and thickened, about 3 minutes. Sift in the flour and beat just until combined.
  • In a separate mixing bowl with clean beaters, beat the egg whites on high speed until frothy, about 1 minute. While beating, slowly add the sugar. Continue beating until stiff peaks form, about 3 minutes. Fold the egg whites into the flour mixture in three batches.
  • Fold in the melted butter. Pour the batter into the prepared pan and gently smooth it into an even layer.
  • Bake for 8 to 10 minutes or until golden brown and springy to the touch. Run a knife around the edges of the cake to loosen from the pan. Invert onto a wire cooling rack and carefully peel off the parchment paper. Let cool completely.

For the Coffee Syrup:

  • In a small saucepan, whisk together the sugar and espresso powder. Whisk in the water and brandy. Place over medium heat and bring to a simmer, stirring occasionally, until the sugar is dissolved. Remove from the heat and let cool.

For the Chocolate Glaze:

  • In a small pot, bring 2 inches of water to a simmer over medium-high heat. Reduce the heat to low.
  • Combine the chocolate and butter in a large heat-proof bowl and set over the pot making sure it doesn’t touch the water. Stir the mixture until the chocolate and butter are fully melted and combined. Remove from the heat and let cool, stirring occasionally, until thickened and spreadable but still glossy. Make the buttercream while it cools.

For the Coffee Buttercream:

  • In a small bowl, dissolve espresso powder in 1 tablespoon of water. Set aside.
  • In the bowl of a stand mixer fitted with the whisk attachment, add the egg yolks. Beat on medium-high speed until thickened, about 6 minutes.
  • Meanwhile, combine the sugar and the remaining 3 tablespoons of water in a medium saucepan and place over medium-high heat. Swirl occasionally until the sugar is dissolved. Insert a candy thermometer, and bring to a boil.
  • Continue boiling the sugar until it reaches 240F. Immediately remove from the heat.
  • With the mixer running, carefully and slowly pour the sugar syrup into the egg yolks in a steady stream. Beat the egg yolk mixture on medium-high speed until very stiff, gathering around the beater, and the outside of the bowl is barely warm to the touch, about 10 minutes.
  • Decrease the speed to medium and add the butter, a tablespoon at a time, waiting a few seconds between each addition. (If your butter feels too cold, squeeze the piece between your fingers to warm them a bit before adding to the bowl.)
  • Beat on medium speed until the buttercream is spreadable and smooth, about 3 minutes. While beating, slowly drizzle in the coffee. Scrape down the bowl and beat until well combined. Cover and set aside.

For the Assembly:

  • Transfer the cooled cake to a cutting board. Cut a 4 ½-inch wide strip down one long side of the cake, creating two long pieces. Cut both pieces in half crosswise creating 4 pieces (2 large rectangles and 2 thinner strips).
  • Place one large rectangle on a cake plate. Brush with a third of the cooled coffee syrup. Spread half of the coffee buttercream evenly over the cake and all the way to the edges.
  • Place the two 4½-inch wide strips side-by-side on top of the buttercream. (The seam will be covered by the next layer.) Brush with half of the remaining coffee syrup. Spread half of the chocolate glaze over the cake all the way to the edges.
  • Top with the remaining pieces of cake and brush with the remaining coffee syrup. Spread the remaining buttercream over the cake making it as smooth as possible. Chill for 30 minutes or until the buttercream is firm on top.
  • Reheat the remaining chocolate glaze for 10 to 15 seconds in the microwave or over simmering water, just until glossy again not hot. Place 2 tablespoons in a piping bag or the corner of a ziptop bag and set aside. Spread the remaining glaze into a thin even layer over the top of the cake, making sure you go all the way to the edge. (Don’t worry if it drips over the side a bit.) Chill until firm, about 2 hours.
  • When firm, trim away a bit on each side of the cake to create clean straight sides. Rewarm the glaze in the piping bag with your hands or run warm water over it. Snip the tip of the bag off and decorate by writing “Opera” on the top of the cake, or pipe as desired. Cake can be loosely covered and refrigerated for up to 4 days.

Video

Notes

  • If your French buttercream appears curdled after adding the butter, it most likely means the egg yolk mixture or butter was too cold when beating them together. To quickly fix this, lightly graze the top of the buttercream with a kitchen torch or hairdryer on low for a few seconds to warm the surface. You could also run the outside of the mixing bowl under hot water for a few seconds. Then, continue whipping. Repeat if needed. The mixture should turn silky and hold peaks.
  • Avoid over-mixing the batter as you risk over-developing the gluten leading to a tough, dry, and dense cake. You also do not want all the egg whites to deflate.
  • I highly recommend using a scale to measure your almond flour and all-purpose flour as it’s the most accurate method. If you add too much flour to the cake batter, you’ll have a dense cake. If you don’t have a scale, then fluff your flour with a spoon and spoon it into your cups before leveling it off with a knife. This method is the best way to measure flour without overpacking the measuring cup.
  • If the flours and powdered sugar have clumps, make sure to sift them before using them. Doing so will prevent a lumpy batter.
  • If your ganache is too runny, let it cool down to set or add more chopped chocolate.
  • Chopping chocolate into finer pieces adds surface area for the butter to help melt the chocolate faster. The larger you chop the chocolate, the longer it’ll take to melt.
  • An offset spatula will really help make assembling the cake much more manageable.

Nutrition

Calories: 670kcal | Carbohydrates: 44g | Protein: 10g | Fat: 50g | Saturated Fat: 26g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 12g | Trans Fat: 1g | Cholesterol: 271mg | Sodium: 56mg | Potassium: 210mg | Fiber: 3g | Sugar: 35g | Vitamin A: 1192IU | Calcium: 80mg | Iron: 3mg