Melt the couverture chocolate, place in a piping bag and pipe small blobs on aluminium foil. Leave to dry.
Put the sugar into a small pan with the salt and heat until caramelised to a golden brown colour.
Stir in the espresso and boil for 3-4 minutes until reduced. Transfer to a bowl and leave to go cold, then stir in the mascarpone.
Whip the cream and fold in. Spoon the coffee cream carefully into cups (or glasses if you prefer) and decorate with the chocolate drops.