Dirty Chai Opera Cake (Gâteau Opéra)

Chai Joconde Sponge:

1. Heat oven to 450°F. Grease and line a jelly roll pan with parchment paper. (We used this 9.5" x 14.5" jelly roll pan because that’s what we have. You could also use an 11" x 17" jelly roll pan; just make sure to shorten the baking time by a few minutes.)
2. In the bowl of your stand mixer, sift together almond flour, confectioners’ sugar, flour, ginger, cinnamon, salt, cloves, nutmeg, and black pepper.
3. Add eggs and egg yolk. Attach paddle and beat until combined.
4. Use a little bit of lemon juice or white vinegar to wipe down another mixer bowl and the whisk attachment of your mixer. Place egg whites in bowl and whip at medium speed.
5. Once egg whites start to get a little frothy, slowly add the caster sugar a teaspoon at a time. Continue beating until stiff, glossy peaks form, taking care not to overbeat the meringue.
6. Gently fold meringue into almond flour mixture, being careful to not knock all the air out.
7. Drizzle slightly cooled melted butter onto batter, gently folding until combined (but not deflated!).
8. Pour batter into prepared pan, smoothing top with an offset spatula or the back of a spoon.
9. Bake 5–10 minutes, depending on the size of your jelly roll pan. Cake is done when it’s golden and springs back when lightly pressed.
10. Transfer pan to wire rack and allow to cool for 15 minutes. Then flip sponge out onto wire rack and allow to cool completely.

Coffee Syrup:

1. In a tiny bowl or shot glass, mix espresso powder and 1 tablespoon water until dissolved. Set aside.
2. In a small pot, combine remaining 4 tablespoons (57g) water and sugar over medium-high heat. Bring to a boil and stir until sugar is dissolved.
3. Remove from heat, then stir in espresso. Set aside and allow to cool to room temperature.

Coffee French Buttercream:

1. In a tiny bowl or shot glass, mix espresso powder and 1 tablespoon water until dissolved. Set aside.
2. In the bowl of a stand mixer fitted with whisk attachment, beat egg yolks until they are thick and foamy.
3. While egg yolks are being whisked, combine sugar and remaining ½ cup (114g) water in a small saucepan. While stirring, heat on low until sugar dissolves. Then increase heat to medium-high and bring mixture to a boil.
4. Cook sugar mixture until it reaches 240°F (soft-ball stage). Upon reaching soft-ball stage, remove saucepan from heat immediately.
5. With mixer on low, slowly pour sugar hot syrup into bowl with egg yolks. Add espresso.
6. Keep mixing until entire bowl is cool to the touch and the yolk and sugar mixture is room temperature.
7. Increase mixer speed to medium. Add butter to bowl one cube at a time, allowing each piece to be fully incorporated before adding the next cube.
8. Add salt. Keep mixing until buttercream is creamy and smooth (5–6 minutes).
   NOTE: If your sugar/water mixture went a little past soft-ball stage and you end up with a few sugar chunks in your frosting, don’t fret! After the buttercream is finished, run it through a sieve to remove any sugar bits. Then beat with a mixer for a couple minutes.

Chai Chocolate Glaze:

1. In a heatproof bowl, melt butter and 6 ounces (170g) drinking chocolate in microwave in 20-second increments, stirring after each zap. Microwave until mixture is mostly melted. Add remaining 1 ounce (28g) drinking chocolate, mixing to combine and melt the rest of the chocolate.
2. Let cool to room temperature and thicken to a spreadable consistency.
   NOTE: If you’re feeling impatient, you can speed up this process by cooling down the glaze in the fridge. Chill for 15­–30 minutes, stirring every 5 minutes.

Assembly & Decoration:

1. Assembly time! Opera cake may seem complicated, but it’s really just a layer cake. Here is the order of assembly (so, bottom to top):
   Joconde sponge
   Coffee syrup
   French buttercream
   Joconde sponge
   Coffee syrup
   Chocolate glaze
   Joconde sponge
   Coffee syrup
   French buttercream
   Chocolate glaze
2. Trim just a smidge off all edges of your joconde sponge. Then, along the wider side, cut sponge into equal thirds. (A ruler is your friend here for measuring and cutting straight lines!)
3. Place one layer on a large dish. Using a pastry brush, brush coffee syrup onto sponge. Take your take—brush on some syrup, let it soak in, brush on some more—until you’ve used about a third of the coffee syrup.
4. Using an offset spatula, spread half of buttercream (around 210g) over soaked sponge.
5. Place second layer of sponge on top of buttercream. Brush on half of remaining coffee syrup.
6. Pour/spread half of chocolate glaze (about 140g) over soaked sponge.
7. Place final layer of sponge on top of chocolate glaze. Brush on remaining coffee syrup.
8. Using an offset spatula, spread remaining buttercream over soaked sponge.
9. Chill cake for about 30 minutes.
10. Once cake has chilled, reheat your remaining chai chocolate glaze in microwave in 15-second increments until pourable and shiny. Pour/spread remaining glaze over cake, spreading evenly with an offset spatula or back of a spoon.
    NOTE: Traditionally, any leftover glaze from this step is used to pipe “Opéra” on top, but we went for more sparkly decor.
11. Place cake back in fridge to chill until firm.
12. Once cake is nice and firm, use a sharp knife to trim away a smidge of cake edges if needed (e.g., if some chocolate glaze dribbled down the side).
13. Cut cake into four 2-inch-wide pieces. (A ruler is your friend here, too!) If adding any gold/silver leaf or gold/silver stars like we did, do so now!
14. Refrigerate the cake pieces until you’re ready to serve them. Allow cake to come to room temperature before you share, as cold buttercream = hard buttercream.