This dish makes a great Friday night supper. Everywhere you go along the coastline of Italy it will be offered to you in some form or another, perhaps with cozze e vongole (mussels and clams), patelle (limpets) and moscardini (baby octopus), scallops, squid, and/or a combination of all of them.
Be careful with the harissa. Not only do samples vary enormously in strength, but also be aware that some jars that bear the name are not really harissa, but a paste made red with beetroot and carrot.
People often tell me that cooking with shellfish is something which they find intimidating. It is really a case of just bunging the shellfish into the pan, then standing back and letting the hob do the work for you.
This is best served as a starter. Sucking the sweet sauce off the juicy crustaceans is an experience to be savoured, never hurried. Shelled and unshelled prawns are both fine to use. Serve with a green salad and hunks of crusty bread.