Using a large lidded, non-stick frying pan or wok, dry fry the chorizo and onions for about 10 minutes until the fat has drained from the sausage and cooked the onions to tender. Add the rest of the vegetables to the pan, including the canned tomatoes and Herbs de Provence, mixing well. Cover and gently simmer for about 40 minutes until all the vegetables are tender.
Preheat the oven to 200 degrees C
Tip into an oven-proof casserole dish, sprinkling with handfuls of grated cheese and the mozzarella. Sprinkle with paprika and the torn basil leaves then bake until the cheese has browned and the bake is bubbling.