Heat the oil in a large non-stick frying
pan, then season the chicken and fry,
flattest-side down, for 4-5 mins. Turn
the chicken over, add the onion and
cook 4-5 mins more. Lift the chicken
from the pan and set aside. Add the
garlic to the pan, then continue cooking
until the onions are soft.
Tip in the tomatoes with the balsamic
vinegar, olives, stock, half the basil
and seasoning, then simmer, stirring
frequently, for 7-8 mins until pulpy.
Return the chicken and any juices to
the pan and gently simmer, covered,
for 5 mins more, to cook the chicken
through. Serve scattered with the
rest of the basil.