Makroud — semolina pastry stuffed with date paste, deep-fried, and dipped in honey — is Kairouan's most famous contribution to Tunisian cuisine, and the city takes it seriously. The medina has a concentration of pastry shops and stalls specialising in it, most concentrated near the main entrance to the medina and along the main souk street.
The best versions are made fresh throughout the day; you want them still warm, the exterior just slightly crisp, the date filling yielding and sweet. They are cheap, filling, and genuinely delicious. Buy a small bag and eat them while walking the medina. The shops also make and sell other traditional Tunisian sweets — almond pastries, fruit jams, nougat — which make good gifts if you are carrying them home.