Opera cake
Opera is an exercise in precision: six layers, each a few millimetres thick, stacked perfectly level. The layers must be thin because the cake is eaten in small pieces — and each piece must contain all six. Soaking the sponge with coffee is generous, not token: dry joconde ruins the whole cake.
Your own work in that: 0 min.
- Joconde sponge 30 min
- Coffee buttercream 25 min
- Chocolate ganache 15 min
- Layering 45 min
- Chilling 180 min
Step by step
0 / 7 doneBake thin joconde sheets
Heat the oven to 210°C. Whip the whole eggs with the almond flour and icing sugar for 8 minutes into a pale, fluffy mixture. Separately whip the whites with the sugar to a glossy, stiff meringue and fold it gently into the mixture, then the sifted flour and melted butter. Spread thinly on two lined trays of about 30 × 40 cm and bake 8 minutes at 210°C. About 30 minutes in all.
Ingredients: 150 g almond flour · 150 g icing sugar · 4 pcs eggs · 4 pcs egg whites · 40 g plain flour · 30 g butter · 30 g sugar
TipEach sheet should be 5 mm. Thicker joconde throws the proportions off and the cake loses its cross-section look.
Thin, flexible sheets that do not tear when lifted.Make the coffee soak
Boil the strong espresso with the sugar, cool and add the rum. The soak should be bitter and strong — it is the only coffee note besides the buttercream, and diluted it disappears between the chocolate and butter.
Ingredients: 200 ml coffee · 50 g sugar · 2 tbsp rum
Make the buttercream on cooked syrup
Boil the sugar with the water to 118°C and pour the hot syrup in a thin stream into whipping yolks. Whip until the mixture cools to room temperature, then add the soft butter piece by piece. Finally stir in the coffee dissolved in a spoonful of boiling water.
Ingredients: 250 g butter · 150 g sugar · 4 pcs egg yolks · 60 ml water · 3 tbsp coffee
TipThe butter and the egg mixture should both be at a similar room temperature. A big difference splits the cream.
Make the ganache
Bring the cream to the boil and pour it over the chopped chocolate. Wait a minute, stir from the centre outwards until the emulsion comes together, then add the butter. Set aside a third for the glaze and cool the rest to spreading consistency.
Ingredients: 300 g dark chocolate · 250 ml whipping cream (30%) · 40 g butter
Soak generously
Cut three equal 20 × 30 cm rectangles from the joconde sheets. Soak each with the coffee syrup generously, with a brush — the sponge should darken visibly and give under a finger. This is the most commonly skipped step and the usual cause of a dry opera.
Ingredients: 200 ml coffee · 50 g sugar · 2 tbsp rum
The sponge should darken and yield — only then is it soaked enough.Build six layers
Stack in order: joconde, coffee buttercream, joconde, ganache, joconde, buttercream. Level every cream and ganache layer with a spatula and freeze the cake for 10 minutes before adding the next — about 30 minutes of breaks in all. Without that the layers merge.
Ingredients: 250 g butter · 150 g sugar · 4 pcs egg yolks · 60 ml water · 3 tbsp coffee
Every layer level and chilled before the next goes on.Glaze and chill
Warm the reserved ganache to 32°C, pour it over the top and spread it in a single pass of the spatula. Chill 3 hours. Slice with a hot knife, wiped after every cut — otherwise the layers smear.
Ingredients: 300 g dark chocolate · 250 ml whipping cream (30%) · 40 g butter
One pass of the spatula — corrections leave marks.
Before you start
Spread it over two days
Day 1: sponge, soak and ganache. Day 2: buttercream, assembly and glaze. The cake has to chill three hours anyway.
Even layers
Use a 20 × 30 cm metal cake frame or build one from folded foil. Without a frame the sides are ragged and the cross-section loses its effect.
Serving
Opera is served in small rectangles — it is very intense. Take it out of the fridge 20 minutes before slicing.
