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.

　　

Ingredients

Serves 8

　　

For caramelizing onions

5 tablespoons unsalted butter

　　2 1/2 pounds onions, peeled, halved lengthwise, and cut into 1/4-inch-thick slices

　　1 teaspoon sugar

　　

For soup

1 tablespoon all-purpose flour

　　7 cups basic brown stock (page 50) or white beef stock (page 42)

　　3 tablespoons cognac

　　1/2 cup dry white wine

　　Coarse salt and freshly ground pepper

　　

For croutons

1/2 baguette, cut into 16 rounds (3/4 inch thick)

　　3 tablespoons unsalted butter, melted

　　6 ounces gruyère cheese, grated on the large holes of a box grater (4 cups)

　　

Step 1

Caramelize onions Melt the butter in a medium Dutch oven or stockpot over medium-high heat. Add onions and sprinkle with sugar. (The pot will be quite full but the onions will cook down significantly.) Cook, stirring only occasionally to prevent sticking, until onions are translucent, about 15 minutes. Reduce heat to medium and continue cooking, stirring frequently, until onions have turned deep brown, 30 to 45 minutes more. (If the onions are sticking to the bottom of the pot, or browning unevenly, stir in a tablespoon of water. Adjust heat if onions are cooking too quickly or too slowly.)

　　

Step 2

Make soup Sprinkle flour over onions and stir to combine, then stir in wine and Cognac. Bring to a simmer over medium heat. Cook 2 minutes, then stir in stock. Partially cover the pot and cook until flavors have melded, 20 to 25 minutes. Season with salt and pepper.

　　

Step 3

Meanwhile, toast croutons Heat broiler. Spread bread slices on a baking sheet and broil, turning once, until lightly toasted, 2 to 4 minutes (watch carefully so they don’t burn). Brush both sides with the melted butter.

　　

Step 4

Broil and serve Divide soup among eight flameproof crocks or bowls. Float two croutons in each crock and sprinkle with 1/4 cup cheese. Broil until cheese is melted and browned in spots. Serve immediately.

　　Reprinted with permission from Martha Stewart's Cooking School: Lessons and Recipes for the Home Cook by Martha Stewart. Copyright © 2008 by Martha Stewart. Published by Crown Publishing. All Rights Reserved.Martha Stewart is the author of dozens of bestselling books on cooking, entertaining, gardening, weddings, and decorating. She is the host of The Martha Stewart Show, the Emmy-winning, daily national syndicated program, and founder of Martha Stewart Living Omnimedia, which publishes several magazines, including Martha Stewart Living; produces Martha Stewart Living Radio, channel 112 on SIRIUS Satellite Radio; and provides a wealth of ideas and information on www.marthastewart.com.