Wash the shellfish under running water, scraping the shells with a sharp knife or scourer if necessary.
Put them in a large pan with a little water over a gentle heat until they open.
Keep the water but strain it to remove any particles of grit.
Heat the oil and add the finely chopped garlic.
When the garlic begins to change colour, add the shellfish and a little of their water.
Cook gently for about 5 minutes, then add a small piece of chilli.
Add salt if necessary.
Cook the pasta, following packet directions carefully to avoid overcooking.
Drain, turn into a heated dish and stir in the sauce.
Sprinkle with parsley and serve