What broth is used in the French Onion Soup?

French Onion Soup traditionally uses beef bone broth as its base. This choice is fundamental to the soup's rich and savory flavor profile, which is characteristic of this classic dish. The beef broth enhances the natural sweetness of the caramelized onions, providing depth and complexity to the soup.

Using beef bone broth not only contributes umami and richness but also pairs beautifully with the flavors imparted by the melted cheese and bread typically served on top. This combination allows the soup to achieve a luxurious mouthfeel and satisfying taste that is beloved in French cuisine.

In contrast, chicken broth tends to be lighter and would not deliver the same intensity of flavor. Vegetable broth, while a viable option for vegetarians, lacks the deep richness typically sought in traditional French Onion Soup. Pork bone broth, while flavorful, is not a conventional choice for this dish and does not align with the classic recipe that emphasizes beef flavors.