Line the base of a charlotte mould or a deep
18cm/7in round cake tin with a piece of baking
parchment.
Place the boudoir biscuits on a tray and sprinkle with half of the
orange flavored
liqueur. Use to line the sides of the mould or tin,
trimming if necessary to make a tight fit.
Mix the
chocolate with the double cream in a bowl and beat
in the egg yolks.
Whisk the egg whites in a large
bowl until standing in stiff peaks, then gradually
add the caster sugar, whisking until stiff and
glossy.
Carefully fold the egg whites into the
chocolate mixture in 2 batches, taking care not to
knock out the air.
Pour into the centre of the mould
and trim the biscuits so they are level
with the
chocolate mixture. Chill for at least 5 hours.