Add all the ingredients for the pears into a pan, bring to the boil, add the pears and take off the heat. Leave to cool down. This is best done a few hours in advance.
Place the chocolate in a metal bowl and place on a pan of simmering water until melted.
Boil the milk and add to the chocolate. Whisk in the egg yolk.
Whisk the egg white and sugar until soft peaks. Add a third of the whites to the chocolate and whisk in. Fold in the rest. Pour into a container and set in the fridge for 20min.
To serve dip a spoon into melted chocolate and flick onto a plate to obtain a streak. Place a pear in the centre and spoon on the chocolate mousse. Finish with a sprig of mint.