Cook the beans in boiling, salted water
until they’ve lost their ‘squeakiness’ but
still have a bit of bite. Drain, plunge into
cold water to cool, then drain again. Tip
them into a kitchen roll-lined bowl and
cover with a sheet of kitchen roll until
ready to serve.
Mix together the sliced shallots, olive
oil, vinegar, sugar and mustard seeds
with some seasoning, then set aside.
To serve, toss the dressing through
the beans in a serving bowl.