1. Bring a large pot of salted water to the boil. Add the asparagus and blanch it until just tender, about 3 minutes.
2. Scoop the asparagus from the water with a large strainer spoon and place in a colander. Run cold water over it to stop the cooking and to preserve the bright green colour. Drain well and slice into small pieces on the diagonal, leaving the tips whole.
3. Bring the water back to a rapid boil and cook the penne until al dente (tender but slightly firm to the bite). Run the pasta under cold water and drain well.
4. In a large serving bowl add the pasta, the blanched asparagus and all the remaining ingredients.
5. Season with salt and pepper, and toss well until all the pasta is well-coated with dressing. Taste for seasoning. This is best served at room temperature. Serves 4 to 5 as a main course, or 6 to 7 as an appetiser or side dish.
Cook's note: Another lovely addition to this dish is around 200g freshly shelled spring peas. Blanch them for 1 minute in the boiling pasta water after you blanch the asparagus. Drain well and add them to the bowl along with the other ingredients.