Bring salted water to a boil in a large saucepan; add beans, cover, and cook 10 to 15 minutes or until crisp-tender. Drain. Plunge into ice water to stop the cooking process; drain.
Melt butter in a saucepan over medium-high heat; add onion and celery, and saute 5 minutes. Add garlic, and saute 2 minutes. Stir in beans, rosemary, salt, and parsley; saute 4 minutes or until thoroughly heated. Prep: 10 min., Cook: 26 min.