70g dark chocolate (ideally 70% cocoa), roughly chopped
5g unsalted butter
For the chocolate glaze
150g good-quality dark chocolate (60% cocoa or more)
20g sunflower oil or similar
Method
To make the sponge, preheat
the oven to 220C/200C F/Gas 7.
Add the 70g egg whites to the
bowl of a mixer with a whisk
attachment and keep the caster
sugar on the side. Separately, in
a jug blender, blitz together the
remaining sponge ingredients,
except the espresso, on full
blast for 8–10 minutes and
transfer to a medium bowl.
Whisk the egg whites to soft
peaks and gradually add the
caster sugar. Continue whisking
until firm peaks form.
Whisk a quarter of the
whipped egg whites into the
sponge mixture and knock it
down vigorously to loosen.
Using a rubber spatula, gently
fold this back into the mixer
bowl with the remaining whipped egg whites until
fully combined.
Line a 38x26cm very flat and
level baking tray with baking
paper. Pour over the sponge
mixture and spread evenly with a
palette knife. Bake for around 10
minutes until it springs back
when pushed gently with your
finger. Slide the sponge with the
baking paper on to a cooling
rack to cool.
In a medium bowl, whisk
together the soft buttercream
and the coffee extract and set
aside. For the ganache, bring the
cream to a quick boil in a small
pan over a medium heat and
pour it straight over the
chopped dark chocolate in a
heatproof bowl. Whisk together
until fully combined. Allow to
cool for 5-10 minutes, then stir in
the butter and set aside.
To assemble, cut the sponge
sheet into three equal strips,
each measuring 22x11cm. Line a
second 38x26cm very flat and
level baking tray with baking
paper or a plastic sheet. Add
80g of the coffee buttercream
and level with a palette knife so
it’s just slightly bigger than one
of the sponge strips.
Place one sponge strip on top,
upside-down, and gently press
the spare baking tray on top to
level. Remove the spare tray and,
using a pastry brush, soak the
top of the sponge with one-third
of the cold espresso coffee.
Top with another 60g coffee
buttercream and spread this with
the palette knife to the edges of
the sponge. Place another strip
of sponge on top and again
gently press with the spare flat
tray to level. Repeat the soaking
with another third of the coffee.
Pour and evenly spread
60–80g of the chocolate ganache
on top and cover it with the last
sponge strip. Gently press again
with the flat tray and soak the
sponge with the remaining
coffee. Transfer to the fridge for a
couple of hours to set.
Lay a sheet of baking paper
on top of the cold cake. Put the
spare flat tray on top of the
paper to sandwich the gâteau and flip over both trays. Lift off
what was the base tray and peel
off the baking paper which
should leave you with a level, flat
coffee buttercream layer - click here, that is
exposed and ready to be glazed.
Slowly melt the chocolate for
the glaze with the oil in the
microwave until it reaches
around 40C, then transfer into a
small jug. Have a large palette
knife ready. Quickly pour the
glaze all over the gâteau and
use the knife to spread it out to
1-2mm thick before it sets. Leave
the glaze to completely set, then
trim the edges neatly using a hot
serrated knife heated up in a tall
jug of hot water or warmed with
a blowtorch. Divide and mark
the gateau into 5cm square
portions with the hot knife, then
fully cut each slice, wiping the
blade with a damp clean cloth
after each cut, and serve.
Recipes and photographs taken from Bake with Benoit Blin by Benoit Blin, photographs by Sam Folan (Hardie Grant, £26).
