Heat the oil in a large pan. Sizzle the
sausages for about 6 mins, turning
occasionally, until brown on all sides, then
remove to a plate. Tip the carrots and
onions into the pan, then cook for 8 mins,
stirring occasionally, until the onions are
soft. Add the vinegar to the pan, then stir
in the drained beans. Pour over the stock,
nestle the sausages in with the beans,
then simmer everything for 10 mins.
Scatter in the frozen peas, cook
for 2 mins more until heated through,
then take off the heat and stir in the
mustard. Season to taste. Serve scooped
straight from the pan.