Clean and wash the leek and mangetouts and cut them into thin strips. Clean, wash and cut the zucchini into diagonal slices. Heat butter in a pan and add leek, sugar snap peas and zucchini, fry briefly.
Add the stock and steam everything for about 8 minutes. After half of the time add peas. In the meantime, cook spaghettini in plenty of boiling salted water for about 5 minutes, drain. Wash the rocket, dab dry.
Finely grate the parmesan. Add pasta and parmesan to the vegetables, mix everything together. Season with salt and pepper. Fold in the rocket at the end. Arrange the vegetable noodles in portions on plates.