To make the pesto, remove any large stalks from the herbs, then put the leaves in a small blender or food processor with the pine nuts, garlic and a little of the oil. Blend until well mixed. Gradually add the remaining oil to form a fairly smooth paste. Add the Parmesan and freshly ground black pepper to taste and process briefly to mix. Set the pesto aside.
Bring a large pot of lightly salted water to a boil. Spread out the zucchini, scallions, peas and fava beans in a steamer basket that will sit snuggly over the pot.
Add the pasta to the pot of boiling water and bring the water back to a boil, then reduce the heat slightly and set the steamer basket on top of the pan. Boil the pasta and steam the vegetables for 11-13 minutes until both are cooked and just tender.
Drain the pasta and turn it into a large serving bowl. Add all the pesto and stir it thoroughly through the pasta, then add the steamed vegetables and toss gently until well mixed. Serve immediately or allow to cool and serve as a salad.
Variations: If you prefer, you can replace the fava beans with thin green beans that have been halved. For a more traditional pesto, use fresh basil leaves rather than cilantro and mint. Flaked almonds work well as an alternative to pine nuts in the pesto.
Each serving: 23.5 g protein, 27 g fat of which 5 g saturates, 54 g carbohydrate, 18 g fibre, 566 Calories