Recipe of the week: French onion soup: Magnifique instead of mediocre

Legend has it that a famished Louis XV of France invented onion soup after finding his larder empty upon returning from a hunting trip, said Charles Kelsey in Cook’s Illustrated. Scrounging up a bag of onions, he added some leftover beef stock and a bottle of Champagne “and created the now-famous recipe.” More recent variations usually include melted cheese and a slice of toasted baguette. Regrettably, too many versions of this recipe also “hide a mediocre broth” under that crust of bread and thick layer of Gruyère. The secret to great onion soup is to coax the magnificent flavor of caramelized onions by patiently cooking them over low heat for three hours. Bread and cheese then become this satisfying broth’s “crowning glory”—still fit for a king.

Recipe of the week

Best French Onion Soup

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Soup

3 tbsp unsalted butter, cut into 3 pieces

6 large yellow onions (about 4 lbs), halved and cut pole to pole

into 1/4 -inch-thick slices

Table salt

2 cups water, plus extra for deglazing

1/2 cup dry sherry

4 cups low-sodium chicken broth

2 cups beef broth

6 sprigs fresh thyme, tied with kitchen twine

1 bay leaf

Ground black pepper

Adjust oven rack to lower-middle position; heat oven to 400 degrees. Generously spray inside of heavy-bottomed large Dutch oven with nonstick cooking spray. Place butter in pot, add onions and 1 tsp salt. Cook, covered, 1 hour. Remove pot from oven, stir onions, scraping bottom and sides of pot. Return pot to oven with lid slightly ajar; continue to cook until onions are very soft and golden brown, 1-1/2 to 1-3/4 hours longer, stirring onions and scraping bottom and sides of pot after 1 hour.

Remove pot from oven and place over medium-high heat. Using oven mitts to handle pot, cook onions, stirring frequently and scraping bottom and sides of pot, until liquid evaporates and onions brown, 15 to 20 minutes, reducing heat to medium if onions are browning too quickly. Continue to cook, stirring frequently, until pot bottom is coated with dark crust, 6 to 8 minutes, adjusting heat as necessary. Stir in 1/4 cup water, scraping pot bottom to loosen crust, and cook until water evaporates and pot bottom has formed another dark crust, 6 to 8 minutes. Repeat process of deglazing 2 or 3 more times, until onions are very dark brown. Stir in sherry and cook, stirring frequently, until sherry evaporates, about 5 minutes.

Stir in broths, 2 cups water, thyme, bay leaf, 1/2 tsp salt, scraping up any final bits of browned crust on bottom and sides of pot. Increase heat to high, bring to simmer. Reduce heat to low, cover, simmer 30 minutes. Remove and discard herbs, then season with salt and pepper.

Cheese croutons

1 small baguette, cut into 1/2 -inch slices

8 oz shredded Gruyère cheese (about 2-1/2 cups)

While soup simmers, arrange baguette slices in single layer on baking sheet; bake in 400-degree oven until bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.

To serve: Adjust oven rack 6 inches from broiler element; heat broiler. Set individual broiler-safe crocks on baking sheet; fill each with about 1-3/4 cups soup. Top each bowl with 1 or 2 baguette slices (do not overlap slices) and sprinkle evenly with Gruyère. Broil until cheese is melted and bubbly around edges, 3 to 5 minutes. Let cool 5 minutes before serving. Serves 6.