I have always wanted to make an opera cake, but was daunted
by reviews that this cake is very time consuming. It’s supposed to have 6 acts-
3 layers of almond sponge, and then espresso-flavored buttercream, chocolate
ganache and a chocolate glaze. It’s definitely a rich cake, but still light
because of the almond sponge. This makes a square shaped cake, which I cut into
16 smaller rectangles. I piped white chocolate “Opera” onto wax paper and transferred
them onto the cake.
Since the cake takes several steps, I made the almond
sponge, espresso buttercream, coffee syrup and chocolate ganache on Thursday
night, assembled the cake and glazed on Friday night, and then cut and transferred
the “Opera” sign onto the cake Saturday. I’m going to freeze this and safe this
for my dad who will be visiting next month!
My modifications:
·
Used a 10 x 15 jelly roll pan. I only have one
pan, so i bake each layer one at a time. My square was 9.25 inches x 9.25
inches. I baked the cake for 7 minutes and 30 seconds.
·
I had some trouble with the sugar in the
buttercream. My sugar crystalized when I poured it so I lost about 3
tablespoons of sugar. I added back in 3 tablespoons of powdered sugar to my
buttercream to make up for the lost sugar.
·
When assembling, I didn’t bother to put the cake
in freezer or fridge to set in between layers. Here what I did when I assembled:
o
Take espresso buttercream and chocolate ganache
out to warm at room temperature if made those the day before
o
Cut out two 9.25 inch x 9.25 inch square. You
will need the leftover sponge as your middle layer, so don’t discard that!
o
Lined square plate with saran wrap, and have
extra hanging out over the plate. Useful later when glazing the cake so that it
can catch glaze that runs over.
o
Put one 9.25 x 9.25 inch square of almond sponge
on square plate. Brush with coffee syrup
o
Spread ¾ of espresso coffee buttercream
o
Put those 2 leftover squares of almond on top of
buttercream. I had to trim one of the halves a tiny bit to make a square. Brush
with coffee syrup
o
Put all of the chocolate ganache on top of this
layer.
o
Put last layer of almond sponge on top. Brush
with coffee syrup.
o
Finish with last ¼ of espresso buttercream.
o
Place in fridge for 1 hour.
o
Make chocolate glaze. Will be very liquidy,
which is why the left over saran wrap in the plate I helpful to catch the
chocolate. Glaze cake.
o
Put cake back in fridge. The chocolate glaze
will harden quickly. After it hardens, you can cover with saran wrap.
o
I melted white chocolate and piped “Opera” onto
wax paper.
o
Next day, I cut the cake into 16 rectangles and transferred the “Opera”
white chocolate signs on top.
Ingredients
The cake:
·
6 large egg whites, at room temperature
·
2 tablespoons (30 grams) granulated sugar
·
2 cups (225 grams) ground blanched almonds
·
2 1/4 cups (225 grams) confectioners sugar, sifted
·
6 large eggs
·
1/2 cup (70 grams) all-purpose flour
·
3 tablespoons (45 grams) unsalted butter, melted and cooled
briefly
The coffee syrup:
·
1/2 cup water
·
1/3 cup sugar
·
1 1/2 tablespoons (7 grams) instant espresso or coffee
The coffee buttercream:
·
2 tablespoons (10 grams) instant espresso or coffee
·
2 tablespoons (15 grams) boiling water
·
1 cup (100 grams) sugar (1 cup sugar does not equal 100 g. I
used 100 g. not sure which was correct…use 1 cup or 100 g)
·
1/4 cup (30 grams) water (I think I also measured out 30 g of
water)
·
Pulp of 1/4 vanilla bean
·
1 large whole egg
·
1 large egg yolk
·
1 3/4 sticks (7 ounces; 200 grams) unsalted butter, at room
temperature
The chocolate ganache:
·
8 ounces (240 grams) bittersweet chocolate, finely chopped
·
1/2 cup (125 grams) whole milk
·
1/4 cup (30 grams) heavy cream
·
4 tablespoons (2 ounces; 60 grams) unsalted butter, at room
temperature
The chocolate glaze:
·
5 ounces (150 grams) bittersweet chocolate, finely chopped
·
1 stick (115 grams) unsalted butter
Instructions
1. To make the cake: Position the racks to divide the oven into thirds
and preheat the oven to 425 degrees F (220 degrees C). Line two 12 1/2-x15
1/2-inch (31-x-39-cm) jelly-roll pans with parchment paper and brush with
melted butter. (This is in addition to the quantity in the ingredient list.)
2. Working in a clean
dry mixer bowl fitted with the whisk attachment, beat the egg whites until they
form soft peaks. Add the granulated sugar and beat until the peaks are stiff
and glossy. If you do not have another mixer bowl, gently scrape the whites
into another bowl.
3. In a mixer fitted
with the paddle attachment, beat the almonds, confectioners sugar and whole
eggs on medium speed until light and voluminous, about 3 minutes. Add the flour
and beat on low speed only until it disappears. Using a rubber spatula, gently
fold the meringue into the almond mixture, then fold in the melted butter.
Divide the batter between the pans and spread it evenly to cover the entire
surface of each pan. (weighed my batter and divided by half)
4. Bake the cakes for 5
to 7 minutes (baked mine for 7 min 30 sec), or until they are lightly browned and just springy to the touch.
Put the pans on a heatproof counter, cover each with a sheet of parchment or
wax paper, turn the cakes over and unmold. Carefully peel away the parchment,
turn the parchment over and use it to cover the exposed sides of the cakes. Let
the cakes come to room temperature between the parchment or wax paper sheets.
(The cakes can be made up to 1 day ahead, wrapped and kept at room
temperature.)
5. To make the syrup: Stir everything together in a small saucepan and
bring to the boil. Cool. (The syrup can be covered and refrigerated for up to 1
week.)
6. To make the buttercream: Make a coffee extract by dissolving the
instant espresso in the boiling water; set aside.
7. Bring the sugar,
water and vanilla bean pulp to a boil in a small saucepan; stir just until the
sugar dissolves. Continue to cook without stirring until the syrup reaches 255
degrees F (124 degrees C), as measured on a candy or instant-read thermometer.
Pull the pan from the heat.
8. While the sugar is
heating, put the egg and the yolk in the bowl of a mixer fitted with the whisk
attachment and beat until the eggs are pale and foamy. When the sugar is at
temperature, reduce the mixer speed to low and slowly pour in the syrup.
Inevitably, some syrup will spin onto the sides of the bowl - don't try to stir
the spatters into the eggs. Raise the speed to medium-high and continue to beat
until the eggs are thick, satiny and room temperature, about 5 minutes.
9. Working with a rubber
spatula, beat the butter until it is soft and creamy but not oily. With the mixer
on medium speed, steadily add the butter in 2-tablespoon (30-gram) chunks. When
all the butter has been added, raise the speed to high and beat until the
buttercream is thickened and satiny. Beat in the coffee extract. Chill the
buttercream, stirring frequently, until it is firm enough to be spread and stay
where it is spread when topped with a layer of cake, about 20 minutes. (The
buttercream can be packed airtight and refrigerated for 4 days or frozen for 1
month; before using, bring it to room temperature, then beat to smooth it.)
10. To make the ganache: Put the chocolate in a medium bowl and keep it
close at hand. Bring the milk and cream to a full boil, pour it over the
chocolate, wait 1 minute, then stir gently until the ganache is smooth and glossy.
11. Beat the butter
until it is smooth and creamy, then stir it into the ganache in 2 to 3
additions. Refrigerate the ganache, stirring every 5 minutes, until it thickens
and is spreadable, about 20 minutes. (The ganache can be packed airtight and
refrigerated for up to 3 days or frozen for 1 month; bring to room temperature
before using.)
12. To assemble the cake: Line a baking sheet with parchment or wax
paper. Working with one sheet of cake at a time, trim the cake so that you have
two pieces: one 10-x-10-inches (25-x-25-cm) square and one 10-x-5-inches
(25-x-12.5-cm) rectangle. Place one square of cake on the parchment and moisten
the layer with coffee syrup. Spread about three-quarters of the coffee
buttercream evenly over the cake. (If the buttercream is soft, put the cake in
the freezer for about 10 minutes before proceeding.) Top with the two
rectangular pieces of cake, placing them side by side to form a square; moisten
with syrup. Spread the ganache over the surface, top with the last cake layer,
moisten, then chill the cake in the freezer for about 10 minutes. Cover the top
of the cake with a thin layer of coffee buttercream. (This is to smooth the top
and ready it for the glaze - so go easy.) Refrigerate the cake for at least 1
hour or for up to 6 hours; it should be cold when you pour over the glaze. If
you're in a hurry, pop the cake into the freezer for about 20 minutes, then
continue.
13. To glaze the cake: Bring the butter to a boil in a small
saucepan. Remove the pan from the heat and clarify the butter by spooning off
the top foam and pouring the clear yellow butter into a small bowl; discard the
milky residue. Melt the chocolate in a bowl over—not touching—simmering water,
then stir in the clarified butter. Lift the chilled cake off the
parchment-lined pan and place it on a rack. Put the rack over the
parchment-lined pan and pour over the glaze, using a long offset spatula to
help smooth it evenly across the top. Slide the cake into the refrigerator to
set the glaze and chill the cake, which should be served slightly chilled. At
serving time, use a long thin knife, dipped in hot water and wiped dry, to
carefully trim the sides of the cake so that the drips of glaze are removed and
the layers revealed.
Keeping: Each element of the cake can be made ahead, as can the
assembled cake. The cake can be kept in the refrigerator, away from foods with
strong odors, for 1 day, or you can freeze the cake, wrap it airtight once it
is frozen, and keep it frozen for 1 month; defrost, still wrapped, overnight in
the refrigerator.
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