FRENCH ONION SOUP

FRENCH ONION SOUP SHOULD HAVE A DARK, rich broth, intensely flavored by a plethora of seriously cooked onions, covered by an oversized crouton that is broth-soaked beneath and cheesy and crusty on top. The first obstacle to success is the broth. This soup is most commonly made with homemade beef stock. But making beef stock takes at least three hours. We wondered if there was a way to get around this step.

We tested soups made with chicken stock, both homemade (which takes considerably less time to prepare than beef stock) and canned. Both were, well, too chicken-y and just not right. Soups made with canned beef broth were terrible. Canned beef broth does not have enough flavor to carry the day alone. After experimentation, we devised a formula for what we call cheater broth. By combining canned beef and chicken broths with red wine (the secret ingredient here), we came up with a broth that has enough good, rich flavor to make an excellent soup base.

The next obvious step was to examine the onion factor. After a crying game of slicing many onions of several varieties and then sautéing away, we found Vidalias to be disappointingly bland and boring, white onions to be candy sweet and one-dimensional, and yellows to be only mildly flavorful, with just a slight sweetness. Red onions ranked supreme. Their flavor was intensely onion-y, sweet yet not cloying, and subtly complex.

What was exasperating about the onions is that they took nearly an hour to caramelize. On top of that, they required frequent stirring to keep them from sticking to the bottom of the pot and burning. We found that adding salt to the onions as they began to cook helped draw out some of the water and shaved about 10 minutes off the cooking time. But we began to wonder if it was necessary for the onions to be so caramelized.

We tried, as one recipe suggested, sautéing them until just softened and colored, but they didn't brown enough to contribute much flavor to the soup. Maybe, we thought, a vigorous sauté, over high heat to achieve deep browning, would do the trick. Not so. Onions cooked that way did not lose enough liquid and made the soup watery and bland. (Besides, there is something wrong with an onion soup in which the onions have even a hint of crunch.) We also tried roasting the onions, thinking that the even, constant heat of the oven might be the answer. Wrong again. Taking the pan in and out of the oven to stir the onions was an incredible hassle.

It was inattentiveness that caused us to let the drippings in the pot of a batch of onions go a little too far. The onions themselves, though soft, were not thoroughly caramelized, but all the goo stuck on the pot was. We were sure that the finished soup would taste burned, but we were surprised to find that it was, in fact, as sweet, rich, and flavorful as the soups we had been making with fully caramelized onions. To refine the technique we had stumbled on, we decided that medium-high heat was the way to go and that the drippings should be very, very deeply browned. There's no way around frequent stirring, but this method cut about another 10 minutes off the onion-cooking time, bringing it down to just over 30 minutes.

With all those wonderful, tasty drippings stuck to the bottom of the pot, the deglazing process—adding liquid and scraping up all the browned bits—is crucial. Once the broth is added to the onions, we found that a simmering time of 20 minutes is needed to allow the onion flavor to permeate the broth and the flavors to meld.

Some recipes call for placing the crouton in the bottom of the bowl and ladling the soup over it. We disagree. We opt to set the crouton on top, so that only its bottom side is moistened with broth while its top side is crusted with cheese. The crouton can then physically support the cheese and prevent it from sinking into the soup. To keep as much cheese as possible on the surface, we found it best to use two croutons, instead of only one, to completely fill the mouth of the bowl. A baguette can be cut on the bias as necessary to secure the closest fit.

Traditionally, French onion soup is topped with Swiss, Gruyère, or Emmentaler. Plain Swiss cheese was neither outstanding nor offensive. It was gooey, bubbly, and mild. Both Gruyère and Emmentaler melted to perfection and were sweet, nutty, and faintly tangy, but they were also very strong and pungent, overwhelming many tasters' palettes.

We found that the flavor of Swiss cheese could be improved with the addition of some grated Asiago cheese. Like Gruyère and Emmentaler, Asiago has a sweet and nutty flavor, but without the pungent quality. Parmesan was a good complement for the Swiss cheese, too, with a pleasant sweetness and saltiness, but without the nuttiness of Asiago.