French Onion Soup

One of the best reasons to make your own basic brown stock is that it means French onion soup from scratch is within easy reach. (You can also make the soup with white beef stock, page 42.) Like many other bistro classics, French onion soup has humble origins as a staple of thrifty households, where a pot of stock—itself born of frugality—was the foundation for many family meals. Even those with limited resources could make soupe a l’oignon since it calls for little else: pounds of inexpensive and readily available onions, a crusty baguette (providing a way to use up day-old bread), and a chunk of sharp Gruyère cheese, grated to turn a little into a lot. Because there are so few components, each one is enhanced in some way to contribute to the final dish. The homemade stock provides both color and robust taste, as well as ensuring a silky consistency. Caramelizing the onions gives them a wonderful sweetness (and more dark brown color). Toasted bread adds a textural note, while gratinéed cheese introduces another pleasing component. Similar to the burnt-sugar shell atop crème brûlée, the molten, golden crown invites tucking into with a spoon. This recipe can be halved, but since the soup freezes well, it is worth making the full amount.