How to Make It
In a large saucepan, cover the black-eyed peas with 2 inches of water. Bring to a boil, cover partially and cook over moderately low heat until tender, about 20 minutes. Drain and let cool slightly.
In a large bowl, whisk the olive oil with the lemon juice and garlic. Add the peas and onion and season with salt and pepper, then toss to coat. Refrigerate for at least 4 hours to let the flavors blend. Bring the salad to room temperature, stir in the parsley and serve.