Six-Onion Soup with Parmesan Croutes

(from castro15’s recipe box)

Categories: Soup


  • 6 tbsp. olive oil, divided
  • 8 cups halved and thinly sliced leeks, white and pale green parts only
  • 2 1/2 cups thinly sliced shallots
  • 1 bunch scallions, thinly sliced
  • 8 garlic cloves, thinly sliced
  • 16 cups halved and thinly sliced sweet onions
  • 8 cups halved and thinly sliced red onions
  • 2 tsp kosher salt
  • 1 tsp black pepper
  • 1/2 cup finely chopped fresh parsley
  • 2 tbsp. finely chopped fresh thyme
  • 2/3 cup dry sherry
  • 10 cups beef broth
  • Parmesan Croutes:
  • 12 slices baguette
  • 2 tbsp. olive oil
  • 1 cup grated Parmesan


  1. To prepare soup: Heat 3 tbsp. oil in a large stockpot over medium heat. Add leeks and cook, stirring occasionally, until softened but not browned, 8-10 minutes. Add shallots, scallions and garlic; cook, stirring, for 1 minute. Add sweet onions, red onions, salt, pepper and the remaining 3 tbsp. oil; stir to combine. Cook, stirring occasionally, until the onions are reduced by half and very juicy, about 45 minutes.

  2. Add parsley and thyme; cook, stirring occasionally, until the mixture is deeply browned, 35-45 minutes more.

  3. Increase heat to high and add sherry. Cook, scraping up any browned bits, for 1 minute. Add broth, cover and bring to a boil. Reduce heat, partially cover and simmer for 15 minutes.

  4. To prepare croutes: Just before serving, position a rack in upper third of oven; preheat broiler on low. Place baguette slices on a baking sheet and brush one side with oil. Broil until golden brown, 4-6 minutes. Turn the slices over and top each with a generous 1 tbsp. Parmesan. Broil until the cheese is melted, 4-6 minutes more. Serve the soup topped with croutes.

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