French Onion Soup

 

3 pounds (1400g) yellow onions, very thinly sliced

6 tablespoons (90g)

1/2 tablespoon sugar, for caramelizing 

kosher salt and freshly ground pepper

1/2 cup (120ml) dry sherry

2 quarts (1.8L) chicken stock

2 sprigs fresh thyme

1 bay leaf 

1 teaspoon fish sauce (optional)

1 teaspoon cider vinegar (optional)

rustic bread or baguette, cut in 1/2 inch slices

1 garlic clove

1 pound (450g) Gruyère cheese, grated

1. in a large saucepan or cast iron skillet, melt butter over medium heat until bubbling 

2. add onions and cook on high for about 8 minutes, stirring occasionally. Turn heat to low , sprinkle with sugar, and cook for 1 to 2 hours, stirring occasionally, and taking care that the onions don't brown too much. Onions should look somewhat like this

3. add sherry and cook until alcohol smell is almost gone. Around 2 minutes

4. add bay leaf, stock, fish sauce, vinegar and thyme, and simmer for 20-30 minutes

5. toast bread slices until nicely browned, and rub with garlic

6. pour soup in individual ovenproof bowls, top with bread slice and cheese

7. place under broiler until cheese is brown and bubbly

This soup can be very well made a day ahead, and it freezes well