Wash the chickpeas under running water and soak overnight. Roast the vegetables with a drizzle of oil and a pinch of salt. Simmer the chickpeas with roast onion, carrot, garlic, prosciutto rind (if using) and bay leaf. Add a drizzle of oil, season with salt and pepper and cook for about 1½ hours. Do not use too much water only the quantity needed to cover the chickpeas.