I was in Tunis recently and very much enjoyed one particular meal at a restaurant that was by locals and cooked traditional food. The restaurant was very hard to find and our map reading skills were not the best, but we were very happy with the range of food we ate there. Harissa seemed to be in most of the food we ate including some mixed in some oil, which was served as a dip as a starter. It had slices of cucumber and black olives in it.
The other was a carrot dip also with Harissa. We dipped our bread into both of them.
I have been making and eating harissa for many years.
Harissa is a hot chilli condiment and ingredient and is the favoured national spice of Tunisia, but it is also popular in Algeria and Libya. It is very common to have harissa with couscous and I first tasted it in Sicily many years ago, which is very close to Tunis.
There are now many books about Middle Eastern cuisine (and North African) with recipes and variations for making it, but this version is very simple. I like to use whole caraway or cumin seeds rather than the powder and I do not usually weigh the chilli flakes, but the following ratio works well. In Tunisia they use a dry, very dark whole chilli, which produces Harissa with an intense colour. The chillies could also be smoked (hence their dark colour).
This photo is in my second book Small Fishy Bites and I took it in Tunis.