Heat oven to 180C/160C fan/gas 4.
Butter 6 x 150ml ovenproof pudding
moulds and put a disc of baking
parchment in the base of each.
To make the sponge, put the butter,
chocolate and coffee in a bowl over a pan
of simmering water. Gently heat until
melted, add the vanilla and stir to combine.
Set aside to cool a little. Sift the flour, cocoa
and bicarb into another bowl, then scatter
in the sugar, breaking up any clumps of
sugar with your fingers. Mix the eggs and
yogurt in a jug. Add the chocolate mixture
and the egg mixture to the flour, and stir
everything with a spatula until there are no
visible lumps of flour. Divide the mixture
between the 6 moulds, put on a baking tray
and cook in the centre of the oven for
30 mins or until a skewer pushed into the
cakes comes out clean. Leave to cool for
10 mins, then turn out onto a wire rack
and cool completely. Can be made up to
5 days ahead, wrapped well in cling film
and stored in a sealed container; or freeze
for up to 6 weeks.
While the cakes cool, make the
chocolate mousse. Melt the chocolate
in a small bowl over a pan of simmering
water. Leave to cool for 5 mins, then stir
in the egg yolk. Whisk the egg white in
another bowl until stiff, add the sugar and
continue to whisk until glossy and thick.
Pour the cream into a third bowl and
lightly whisk until thick. Tip the cream
into the chocolate and stir to combine.
Add the beaten egg white and, using a
metal spoon, fold together until there
are no streaks of egg white remaining.
Chill until needed.
Line each pudding mould with cling
film. Remove the tops of the cakes with
a small serrated knife to create a flat
surface. Carefully split the cakes into
2 or 3 layers through their middles.
Reassemble the cakes in the pudding
moulds, soaking each layer of sponge with
the liqueur and layering with chocolate
mousse. Cover the cakes with any
overhanging cling film and press down
gently. Chill the cakes for at least 3 hrs
or for up to 2 days before serving.
Melt the white chocolate in a small
bowl over a pan of barely simmering
water. Turn each cake out and unwrap.
Drizzle the top of each with a little white
chocolate, letting it drizzle down the sides.
Decorate using a small sprig of real or
artificial holly. Leave the white chocolate
to set for 20 mins before serving.