1.Place half the pepitas, the rocket, basil, parmesan, lemon juice, oil and ½ cup (125ml) water in a food processor; process until smooth. Season to taste.
2.Cook pasta in a large saucepan of boiling salted water until al dente. Drain, reserving ¾ cup (180ml) pasta water.
3.Meanwhile, heat extra oil in a large frying pan over medium heat; cook leek, stirring, for 3 minutes or until tender. Stir in beans and peas; cook for a further 2 minutes, lightly crushing some of the mixture with a potato masher or fork. Season.
4.Stir in the pepita pesto and reserved pasta water until well combined. Add the pasta; toss gently to coat well. Remove from heat; stir through the extra rocket.
5.Serve pasta topped with remaining pepitas, extra basil and extra parmesan. Drizzle with a little more oil, if you like, and serve with lemon wedges.
You can use any short pasta shape you prefer. Save the green tops of the leeks for adding flavour to soups and stocks.