Soak clams in fresh water for 30 minutes. Pull the clams out of the water, do not strain. Discard any opened or cracked clams.
Cook pasta according to package instructions.
In a large sauté pan, heat the butter and olive oil. Add garlic and onion and sauté for 45 seconds. Add the clams, the white wine, the lemon juice and half the parsley and cook for 5 to 10 minutes, until all the clams have opened.
Add pasta to clam mixture and toss to coat. Season with black pepper and sprinkle with remaining parsley.
