-
Preheat the oven
to 200C/400F. Spread out the hazelnuts on a baking
sheet and toast them in the oven for 5 minutes until
golden. Transfer the nuts to a clean dish towel and
rub off the skins. Cool, then chop finely.
-
Lien a 1.2
liter/5 cups loaf tin with clear film and cut the
sponge fingers to fit the base and sides. Reserve
the remaining biscuits.
-
Mix the coffee
with the Cognac or other brandy in a shallow dish.
Dip the sponge fingers briefly into the coffee
mixture and return to the tin, sugary-side down.
-
Whip the cream
with the icing sugar until it holds soft peaks.
Roughly chop 75g/3oz of the chocolate, and fold into
the cream with the hazelnuts.
-
Melt the
remaining chocolate in a heatproof bowl set over a
saucepan of barely simmering water. Cool, then fold
into the cream mixture. Spoon into the tin.
-
Moisten the
remaining biscuits in the coffee mixture and lay
over the filling. Wrap and freeze until firm.
-
Remove the gateau
from the freezer 30 minutes before serving. Turn out
on to a serving plate and dust with icing sugar and
cocoa powder.