Purge the clams if they are not already purged (some fishmonger will sell them already purged): Place clams in a large bowl of cold, salted water (about 1 tablespoon sea salt per litre of water). Let them sit for 1 hour in the fridge to expel any sand. Drain and rinse thoroughly.
Rinse the clams under cold running water again, discarding any that are open and do not close when tapped.
Heat the olive oil in a large sauté pan over medium heat. Add the garlic and cook for 30 seconds until fragrant but not browned.
Add the clams and pour in the white wine. Cover with a lid and cook for 3–4 minutes, shaking the pan occasionally, until the clams have opened.
Remove the lid and stir in the parsley. Season with black pepper to taste.
Discard any unopened clams. Transfer to a serving bowl with all the pan juices.
Serve immediately with plenty of crusty bread to soak up the broth.