There is no soup more classic than the French onion soup. It's famous around the world and here in the United States, no bistro menu is without it. It's a soup that is ultimately comforting, flavorful, and adored by everyone who tries it. The best part is breaking through the irresistible topping of bread and melted cheese. No wonder so many people have claimed to be its inventor.
I first came across French onion soup a couple of years ago when a small group of friends and I gathered to celebrate my birthday at Cafe Deville, a rustic French bistro in the East village. We gorged on crusty bread, wine, escargot in butter, and ordered everything that was stereotypically French, including French onion soup. The cheese in that bowl was so stretchy that a knife was needed. It was a very memorable time. Good fun was had by all and the bottle of wine helped too.
To recreate that onion soup, I decided to make my own, inspired by the onion soups of Julia Child and Jacques Pépin. First I start with a base of onions slowly caramelized in butter. To further develop the complex flavors, I add wine and Cognac, followed by stock. A flavorful homemade beef or chicken stock is key to making the best version of this soup. A sprig of thyme and a bay leaf round out the earthy flavors. It's the perfect soup for a cold day enjoyed among family and friends. It makes an ideal appetizer but also works well as a main course. Serve the soup with a glass of wine and everyone will feel warmed right through.
French Onion Soup Gratiné
3 to 4 sweet onions (about 3 pounds), halved lengthwise and thinly sliced
2 tablespoons butter
coarse sea salt
freshly ground black pepper
1 cup white wine
2 tablespoons Cognac
4 cups beef or chicken stock
2 cups water
1 thyme sprig
1 bay leaf
2 cups grated Gruyère
Melt butter in a large pot over medium heat. Add onions in layers, seasoning each layer with salt and pepper. Cook, stirring occasionally, until onions are caramelized and brown, about 40 minutes. Add wine and Cognac. Simmer on medium-low until liquid has reduced and thickened, about 10 to 15 minutes. Add stock, water, thyme, and bay leaf. Simmer 20 minutes.
Preheat oven to 350 degrees F.
Slice baguette into 1/2-inch slices. Place on rimmed baking sheet and bake until dry, about 8 minutes.
Check soup for seasoning. Remove thyme and bay leaf. Ladle soup into oven-proof bowls. Top soup with 2 to 3 baguette slices and 1/2 cup grated Gruyère per bowl. Place bowls on a rimmed baking sheet. Broil until cheese is melted, bubbly, and brown, about 5 minutes. Yield: 4 to 6 servings.