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Easy Six Onion Soup with Baked Parmesan Crisps
4.77 from 13 votes

Onion Soup Recipe

This is my favorite Onion Soup Recipe. Made by slowly caramelizing six different types of onions, it’s comforting, fragrant, flavorful, and especially delicious when topped with baked Parmesan crisps or gooey melted cheese.
Prep Time1 hr
Cook Time3 hrs
Total Time4 hrs
Servings: 6 bowls
Calories: 633kcal

Ingredients

  • 4 tablespoon olive oil - divided
  • 4 tablespoon butter - divided
  • 6 cups leeks - white and light green parts only, halved and thinly sliced
  • 8 large shallots - thinly sliced
  • 2 cups green onions - thinly sliced
  • 6 sweet white onions - halved and thinly sliced
  • 4 red onions - halved and thinly sliced
  • 3 yellow onions - halved and thinly sliced
  • 2 teaspoon salt
  • 1 teaspoon fresh ground black pepper
  • 10 cloves garlic - minced
  • 1 cup fresh parsley - finely chopped
  • 2 tablespoon fresh rosemary - finely chopped
  • 2 tablespoon fresh thyme - finely chopped
  • cup dry sherry - (may substitute with cognac or additional beef broth)
  • 8-12 cups beef broth
  • Fresh chopped parsley - to garnish

For the Baked Parmesan Crisps

  • 1 French or Sourdough baguette - sliced into 1/2-inch thick pieces
  • 3 tablespoon olive oil
  • 1 cup Parmesan cheese - shredded

Instructions

For the Soup

  • Place 2 tablespoons of olive oil and 2 tablespoons of butter in a large heavy-bottomed Dutch Oven or stockpot set over medium-high heat. Add the leeks and cook, stirring often, until starting to soften (approximately 5-6 minutes). Add the sliced shallots to the leeks and mix well to combine. Continue to cook, stirring frequently, for 3-4 minutes. Add the sliced green onions, white onions, red onions, yellow onions, salt, and black pepper.
  • If you find that all the onions refuse to fit into the pot, that's ok! You may need to add part of the onions, allow them to cook down, add some more onions, allow those to cook down, and then add the rest.
  • Drizzle the remaining olive oil over the onions and add the remaining 2 tablespoons of butter to the pot. Cook the onions, stirring frequently until softened, deeply golden-brown, and jammy (about 60-90 minutes). In the last 15 minutes, stir in the garlic, fresh parsley, rosemary, and thyme. Mix well.
  • With the onions deeply browned and caramelized, increase the temperature to high and add the dry sherry (or cognac) and scrape any burnt pieces stuck to the bottom of the pot. Allow the alcohol to cook for approximately 1-2 minutes before adding the beef broth to the pot. Cover and bring to a boil, then reduce the heat to low. Simmer for an additional 20-30 minutes and season with additional salt and pepper, as needed.
  • Serve each bowl topped with homemade baked Parmesan crisps (see below), fresh chopped parsley and additional shredded cheese, if desired.

For the Baked Parmesan Crisps

  • Prepare the Parmesan crisps approximately 15 minutes before the soup is ready to be served. Position the baking rack in the upper third of the oven and preheat the broiler to low.
  • Slice the baguette into thin 1/2-inch slices and transfer to a baking sheet in a single layer. Brush the top side of each slice with oil. Transfer baking sheet to the oven and broil until golden brown, approximately 4 minutes.
  • Remove the baking sheet from the oven and immediately flip over each slice and top with approximately 1 tablespoon of shredded Parmesan cheese. Return the baking sheet to the oven and broil an additional 3-4 minutes or until the cheese has melted. Serve.

Notes

Originally published January 2018

Nutrition

Calories: 633kcal | Carbohydrates: 68g | Protein: 19g | Fat: 31g | Saturated Fat: 10g | Cholesterol: 31mg | Sodium: 2600mg | Potassium: 1054mg | Fiber: 9g | Sugar: 17g | Vitamin A: 3155IU | Vitamin C: 55.9mg | Calcium: 431mg | Iron: 6.5mg
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