1. Heat the olive oil in a large pot. Add the onion and fry gently for 15-20 minutes or until it is translucent. Add the pancetta, rice and garlic and cook for 2-3 minutes, stirring. Pour in chicken stock, add the bay leaf and bring to a boil. Lower the heat and simmer for 15 minutes.
2. Meanwhile, bring a small pan of water to a boil. Add the broad beans and cook for 1 minute. Drain, rinse under cold water to stop the cooking process and cool the beans, then drain again. Peel and discard the skins.
3. Add the peeled broad beans, peas, asparagus tips and courgettes to the soup and cook for 5 minutes or until the vegetables are brightly coloured and just tender. Stir in the chopped herbs and lemon zest, then discard the bay leaf. Season to taste with salt (you won't need much, if any) and black pepper and serve the soup hot.