What is one of the primary components of the lemon vinaigrette served with the Steak Frites?

Lemon juice is a key ingredient in lemon vinaigrette, serving as the foundational element that provides the signature citrus flavor and brightness that complements the Steak Frites. The acidity from the lemon juice helps to balance the richness of the dish, enhancing its overall flavor profile. While other components like vinegar, garlic, and mustard may also play roles in vinaigrettes, lemon juice is distinctly identified for its fresh and vibrant taste, which is essential for achieving the desired character of the lemon vinaigrette.