1. In a small bowl, marinate the shallots in 1/2 cup of sherry vinegar for 15 minutes, then drain and rinse with cool water. Set aside. 2. Meanwhile, simmer beans in 6 cups of boiling, salted water for 3 minutes. Drain and rinse in cool water. set aside. 3. In a small bowl, whisk together the mustard, remaining 2 Tbsp. vinegar, salt and pepper until combined, then slowly whisk in the olive oil. 4. In a large bowl, toss together the beans, shallots, Roquefort cheese and dressing. SErve immediately or refrigerate 3-4 hours until cold.