French Onion Soup (Cooks Illustrated)

By marck

Originally titled "Best French Onion Soup." And you know what? It really is. Takes a long time, but oh my God.....

Ingredients

• SOUP:
• 4 lbs onions, halved and sliced through the root end into 1/4-inch-thick pieces
• 3 Tbsp unsalted butter, cut into 3 pieces
• Salt and pepper
• 2 C water, plus extra for deglazing
• 1/2 C dry sherry
• 4 C chicken broth
• 2 C beef broth
• 6 sprigs fresh thyme, tied with kitchen twine
• 1 bay leaf
• CHEESE CROUTONS:
• 1 small baguette, cut into 1/2-inch slices
• 8 oz shredded Gruyère cheese (2 cups)

Preparation

Step 1

1. FOR THE SOUP: Adjust oven rack to lower-middle position and heat oven to 400 degrees. Generously spray inside of Dutch oven, with vegetable oil spray. Add onions, butter, and 1 teaspoon salt. Cook, covered, for 1 hour (onions will be moist and slightly reduced in volume). Remove pot from oven and stir onions, scraping bottom and sides of pot. Return pot to oven with lid slightly ajar and 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.

2. Carefully remove pot from oven (leave oven on) and place over medium-high heat. Cook onions, stirring frequently and scraping bottom and sides of pot, until liquid evaporates and onions brown, 15 to 20 minutes (reduce heat to medium if onions brown too quickly). Continue to cook, stirring frequently, until bottom of pot is coated with dark crust, 6 to 8 minutes, adjusting heat as necessary. (Scrape any brown bits that collect on spoon back into onions.) Stir in 1/4 cup water, scraping 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.

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

4. FOR THE CHEESE CROUTONS: While soup simmers, arrange baguette slices in single layer on rimmed baking sheet and bake until bread is dry, crisp, and golden at edges, about 10 minutes. Set aside.

5. TO SERVE: Adjust oven rack 7 to 8 inches from broiler element and heat broiler. Set 6 broiler-safe crocks on rimmed baking sheet and fill each with about 1-3/4 cups soup.

TO MAKE AHEAD: Onions can be prepared through step 1, cooled in pot, and refrigerated for up to 3 days before proceeding with recipe. Soup can be prepared through step 3 and refrigerated for up to 2 days.