Vegetable stew is very common in Puglia, but also in Basilicata and in the rest of the south. You can make it in winter and serve it hot and soup-like, or in summer, making it less soupy and served cold on a slice of homemade bread. We like both versions! In addition, it's a dish which lends itself to customization: if you have a sweet pepper or aubergine in the fridge don't hesitate to add them! The Italian name for this stew is 'ciambotta' which seems to refer to the Puglian fish stew variant. Apparently, American soldiers arriving in Puglia at the end of World War II called this dish "jam-boat" or "sea jam", from which derives the Italian 'ciambotta'.
Chop up the onion and fry gently in a dash of oil. First add the potato cut into pieces, then the courgettes and then the tomatoes (for which all you need to do is cut a cross in the skin so they don't burst while cooking), and finally a little celery, parsley and salt. Finish with half a glass of water and cook for 30 minutes. Serve as a side dish or on a slice of homemade bread, adding a little grated 'cacioricotta' cheese on top.