How to Make It
Preheat the oven to 400°. Heat the oil in a large saucepan. Add the onions and cook over high heat, stirring, until nicely browned, 8 to 10 minutes. Add the Basic Chicken Stock, season with salt and pepper and bring to a strong boil.
Meanwhile, spread out the bread cubes on a baking sheet and toast for about 8 minutes, or until lightly golden. Transfer the cubes to a large soup tureen and sprinkle the cheese on top. Pour the boiling soup into the tureen and mix. Ladle into soup plates or bowls and serve.
In a large stockpot, cover the chicken bones with 3 quarts of water and bring to a boil over high heat. Reduce the heat to moderate and boil gently for 30 minutes. Skim the fat from the stock.
Add the remaining ingredients and bring to a boil over high heat. Reduce the heat to moderately low, cover partially and simmer until reduced by half, about 2 1/2 hours.
Strain the stock, pressing down on the solids. Measure the stock; if more than 5 cups, return to the saucepan and continue reducing.