This Italian-style soup uses the lettuce-like frizzy curly endive that's available from August through March. It is perfect for a cold winter's night. Serve with a drizzle of extra virgin olive oil and freshly grated Parmesan cheese.
Make the soup ahead of time; let stand for half an hour, so the curly endive has time to release more flavour. Or prepare the soup a day in advance and gently reheat before serving.