Set the peeled shallots aside and place
all the other ingredients except the balsamic
vinegar into a large saucepan. Bring to the
boil, lower the heat, then simmer for 3 mins.
Drop the shallots into the pan and simmer
for 8-10 mins until just tender. Use a slotted
spoon to scoop the shallots and basil out
into sterilised jars (see Know-how, below),
then boil the liquid vigorously for 5 mins.
Turn the heat off, stir in the balsamic vinegar,
then pour over the shallots to cover. Seal the
jars and leave for at least 3 days. Will keep
for up to 3 months.