Blanch the beans in boiling water
for 3-4 mins until al dente, adding the
spring onions for the final 2 mins. Plunge
the vegetables into ice-cold water, then
drain and set aside.
When ready to serve, heat the oil in
a frying pan, tip in the veg and warm
through. Add the olives, heat a little
longer, then remove from the heat and
stir through the lemon juice, tarragon
and some seasoning.