French Onion Soup

This recipe from Bistro by Sharon O’Connor is courtesy of the celebrated Paris bistro La Poule au Pot.

5 large yellow onions
¼ cup olive oil or butter
1 teaspoon salt
2 cups dry white wine
2 cups dry white or red wine
8 cups low-salt chicken stock or beef stock
Salt and freshly ground pepper to taste
Eight ¾”-inch-thick slices day-old French bread
3 cups shredded Gruyere or Swiss cheese

1. Using a large sharp knife, trim the ends off each onion, and slice them in half lengthwise. Remove the peels and slice thinly into half-moon shapes.
2. In a large, heavy pot over high heat, add the olive oil or butter and heat until hot or melted. Stir in the onions and salt and reduce the heat to medium-high. Cook, stirring occasionally with a wooden spoon, for about 45 minutes, or until the onions are an even deep mahogany brown; scrape up all the browned bits from the bottom of the pan as your cook.
3. Pour in the wine, raise the heat to high, and boil until the soup is reduced by one third. Stir in the stock and bring to a boil. Reduce heat to medium, and simmer for 20 minutes. Season with salt and pepper to taste. (At this point you can refrigerate the soup, covered for up to 3 days; bring to a simmer before continuing.)
4. Place a rack in the top third of the oven and preheat the broiler. Slice country bread into rounds that will fit into the mouth of your soup bowls. Place deep ovenproof soup bowls or crocks on a baking sheet. Ladle the soup into the bowls, about 1 inch to the top. Add a slice of bread to each bowl, and sprinkle the shredded cheese on top. Broil for 1 to 2 minutes, or until the cheese is golden and bubbling. Serve immediately.