This recipe uses three different types of onions: yellow, red, and sweet Vidalia onions. The blend of these onions lends a lovely sweetness to the soup, but if you can't find them use all yellow onions. You will need broiler-proof bowls for this soup.

Three Onion Soup Gratinee

1/4 cup (1/2 stick) unsalted butter 2 Vidalia, Maui or Walla Walla onions (about 1/2 pound total), cut into 1/4-inch thick slices
2 red onions (about 1/2 pound), cut into 1/4 inch slices 2 yellow onions (about 1/2 pound), cut into 1/4 inch slices Freshly ground pepper 2 tablespoons all-purpose flour 1 3/4 cups good quality unsalted beef stock 5 1/2 cups good quality unsalted chicken stock 1 1/2 tablespoons fresh thyme leaves Salt and pepper to taste 4 to 8 thin slices country-style bread, toasted 1 1/2 cups coarsely grated Gouda cheese, such as Winchester Cheese (or use Gruyere or Emmentaler)

In a large stockpot, melt the butter over medium-low heat. Add all the onions along with 1/4 teaspoon pepper, and sautè until the onions begin to turn golden brown or caramelize, about 25 minutes. Stir occasionally to be sure the onions do not stick to the pan. Once the onions are brown, add the flour and stir constantly until it disappears. Turn the heat to medium-high and add both stocks and the thyme. Bring to a boil. Reduce the heat to low, cover and cook until the soup is slightly thickened and is a medium-brown in color, at least 1 hour. Taste and add salt and pepper as needed.
Preheat the broiler. Ladle the soup into broiler-proof bowls. Place 1 slice of toast in each bowl and top with the cheese. Heat under the broiler until the cheese is brown and bubbling, 3 to 5 minutes. Serve immediately.

Serves 4 to 8.