Tip the flour into a mixing bowl and
remove 2 tsp (the cocoa will replace
it later). Add the butter and rub into the
flour until the mixture resembles fine
breadcrumbs. Sift in the cocoa and icing
sugar, then, using a round-bladed knife,
stir in the oil, egg yolk and 1½-2 tbsp cold
water, until the dough comes together.
Gently gather into a ball, then roll out on
a lightly floured surface, big enough to
fit a 20cm round x 3.5cm-deep loose-bottomed
flan tin. Ease the pastry into
the tin, leaving a slight overhang. Lightly
prick the base with a fork, then chill for
about 10 mins.
Heat oven to 190C/170C fan/gas 5. Sit
tin on a baking sheet. Line the pastry with
foil and fill with baking beans. Blind-bake
for 15 mins or until set. Carefully lift out
the beans and paper, then bake the
pastry case for another 10 mins or until
the base is cooked. Remove, carefully
trim off the overhanging pastry with a
sharp knife, to give the pastry a flat edge,
then leave until completely cold.
To make the filling, put the chocolate
in a large bowl that will fit over a pan of
simmering water without touching it. Mix
the cocoa, coffee and vanilla with the milk.
Pour over the chocolate. Sit the bowl over
a pan of gently simmering water, stir, then
immediately remove pan from the heat,
with the bowl of chocolate still over the
water, stirring occasionally, to check when
melted. Stir the melted chocolate – it will
be quite thick. Stir in 2 tbsp boiling water
and the chocolate will immediately thin
down and become silky smooth. Take the
bowl off the pan and leave to cool slightly.
Whisk the egg whites to stiff peaks, then
whisk in the sugar until thick and glossy.
Fold the créme fraîche into the cooled
chocolate. Fold one-third of the egg
whites into the chocolate mixture using
a large metal spoon, then very gently fold
in the remaining whites, a third at a time,
until evenly mixed in. Remove the pastry
case from the tin and place on a serving
plate. Spoon the filling into the case, then
spread out gently and evenly. Chill for
about 3 hours, or overnight, before
serving. Serve with a sifting of cocoa
and half-fat créme fraîche, if you like.
Please note, pregnant women, the
elderly, babies and toddlers, and people
who are generally unwell, should avoid
eating raw or partially cooked eggs.