For each chocolate cup, cut a double
thickness 15 cm/6 in square of foil. Mould it around a small orange,
leaving the edges and corners loose to make a cup shape. Remove the
orange and press the base of the foil case (shell) gently on the work
surface to make a flat base. Repeat to make four foil cups.
For the cups, break the chocolate into
small pieces, place in a bowl set over very hot water. Stir occasionally
until the chocolate has melted. Spoon the chocolate into the foil cups,
spreading it up the sides with the back of a spoon to give a ragged
edge. Chill for 30 minutes or until set hard. Gently peel away the foil,
starting at the top edge.
To make the chocolate mousse, put the
plain chocolate and brewed espresso into a bowl set over a pan of hot
water and melt as before. When smooth and liquid, add the unsalted
butter, a little at a time. Remove the pan from the heat then stir in
the egg yolks.
Whisk the egg whites in a bowl until
stiff, but not dry, then fold into the chocolate mixture. Pour into a
bowl and chill for at least 3 hours. To serve, scoop the chilled mouse
carefully into the chocolate cups. Add a scoop of mascarpone or clotted
cream and decorate with a sprig of fresh mint, if using.