Mexican French Onion Soup
- Servings: 4
- 2 lb medium onions, halved lengthwise, then thinly sliced lengthwise
- 3 sprigs fresh thyme
- 2 Turkish bay leaves or 1 California
- 3/4 teaspoon salt
- 1/2 stick (1/4 cup) unsalted butter
- 2 teaspoons all-purpose flour
- 3/4 cup dry white wine
- 4 cups reduced-sodium beef broth (32 fl oz)
- 1 1/2 cups water
- 1/2 teaspoon black pepper
- 6 (1/2-inch-thick) diagonal slices of baguette
- 1 (1/2-lb) piece Oaxaca Cheese
- Special equipment: 6 (8- to 10-oz) flameproof soup crocks or ramekins; a cheese plane
- Cook onions, thyme, bay leaves, and salt in butter in a 4- to 5-quart heavy pot over medium-low heat, uncovered, stirring frequently, until onions are very soft and deep golden brown, about 45 minutes. Add flour and cook, stirring, 1 minute. Stir in wine and cook, stirring, 2 minutes. Stir in broth, water, and pepper and simmer, uncovered, stirring occasionally, 30 minutes.
- While soup simmers, put oven rack in middle position and preheat oven to 350°F.
- Arrange bread in 1 layer on a large baking sheet and toast, turning over once, until completely dry, about 15 minutes.
- Remove croûtes from oven and preheat broiler. Put crocks in a shallow baking pan.
- Discard bay leaves and thyme from soup and divide soup among crocks, then float a croûte in each. Slice enough Gruyère (about 6 ounces total) with cheese plane to cover tops of crocks, allowing ends of cheese to hang over rims of crocks, then sprinkle with Parmigiano-Reggiano.
- Broil 4 to 5 inches from heat until cheese is melted and bubbly, 1 to 2 minutes.