Thoroughly wash and rinse the clams to remove any dirt or sand. Discard any clams that stay open when gently tapped or where the shells are damaged or cracked.
In a large pan, heat the oil over a medium heat. Add the garlic and fry for 1 minute, then add the white wine.
Increase the heat and boil until the liquid has reduced to half the original volume.
Add the clams, cover with a lid, and steam until the clams start to open, around 3-5 mins.
Add the butter, cover, and cook for another few mins, or until the clams are all open. Discard any that don’t open.
Transfer the clams and cooking liquid to large bowls and serve sprinkled with parsley.