Trim stem ends of green beans; cut beans into 1 1/2-inch lengths.
In a 3- to 4-quart pan, cook beans, uncovered, in boiling salted water just until tender-crisp (about 7 minutes).
Drain; transfer to a serving dish.
In a small bowl, mix butter, pepper, parsley, and lemon juice; pour over beans and toss well.
Season to taste with salt.