Heat
the oil in a saucepan, add the onion, garlic, celery
and carrots, and cook until beginning to brown.
Add
the harissa and stir for 1 minute. Add the
aubergines, tomatoes and the measured water to the
pan.
Bring to the boil then cover the pan and simmer
gently for about 25 minutes.
Stir the okra into the pan, cover and cook for 15-20
minutes until it is tender.
If necessary, uncover
the pan towards the end of cooking so the
consistency of the sauce at the end of the cooking
is quite thick. Add salt to taste.