In a small bowl, combine together the shallot, garlic, mustard (if using), salt, pepper, and vinegar. Whisk in olive oil.
Pour over bean mixture. Sprinkle the bean salad with some fresh basil.
~ Free Tip ~ Serve with crusty bread for a complete meal. Top with crispy bacon. Saute shallot and garlic, then add blanched beans and dressing for a different flavor. Serve as an accompaniment to meat dishes.