The Washington Post

Italian Onion Soup

Italian Onion Soup 6.000

Renee Comet for The Washington Post; styling by Bonnie S. Benwick

Sunday Supper Nov 28, 2017

You’ll need a 6-quart slow cooker. To make this on the stove top, see the VARIATION, below.

Serve with a salad of white bean, marinated artichokes, celery and thinly sliced red onion dressed with olive oil and lemon, on a bed of arugula.


When you scale a recipe, keep in mind that cooking times and temperatures, pan sizes and seasonings may be affected, so adjust accordingly. Also, amounts listed in the directions will not reflect the changes made to ingredient amounts.

Tested size: 6 servings

  • 1/4 cup extra-virgin olive oil
  • 3 pounds yellow onions, very thinly sliced
  • 1 tablespoon minced garlic
  • 1 teaspoon kosher salt, or more as needed
  • 6 sprigs fresh thyme
  • 1 cup dry white wine
  • 2 tablespoons sherry vinegar
  • 6 cups low-sodium beef, chicken or vegetable broth
  • 1 tablespoon fresh lemon juice
  • Freshly ground black pepper
  • Twelve 1/2-inch-thick, diagonally cut baguette slices
  • 2 1/2 ounces coarsely grated Italian fontina cheese
  • 1/2 ounce finely grated Parmigiano-Reggiano cheese
  • 6 large eggs
  • Chopped parsley, for garnish


Combine the oil, onions, garlic, salt, thyme, wine and sherry vinegar in the slow cooker and stir to incorporate. Cover and cook on HIGH for 7 hours, stirring quickly every couple of hours. Add the broth, cover and cook on HIGH for 2 hours.

Discard the thyme sprigs and stir in the lemon juice; taste and season lightly with salt and pepper.

Preheat the oven to 400 degrees. Fill a large, straight-sided saucepan with 2 inches of water and bring to a boil over high heat.

Arrange the bread slices on a rimmed baking sheet in a single layer. Toast (middle rack) for 4 minutes, turning them over once.

Meanwhile, stir together the fontina and Parmigiano-Reggiano in a bowl. Top each toast with the cheese mixture, using all of it.

Break the eggs into individual ramekins or small bowls. Remove the saucepan of boiling water from the heat. Working quickly, pour the eggs one by one into the water, cover and let stand (off the heat) for about 2 minutes, or until the whites are set and the yolks are still jiggly (if you desire an egg that's more well done, leave it in for another minute). Transfer with a slotted spoon to a shallow bowl as they are done.

While the eggs are poaching, bake the fontina toasts (upper rack) for 2 minutes, or until the cheese has melted.

To assemble, ladle the soup into individual bowls, Top each portion with an egg and a sprinkling of parsley. Serve hot, with two toasts per portion, for dunking.

VARIATION: To make this on the stove top, heat the oil in a large Dutch oven over medium heat. Add the onions, thyme and salt; reduce the heat to medium-low, cover with a piece of parchment paper and the lid and cook, stirring occasionally, for 15 to 20 minutes or until the onions are translucent. Uncover; add the garlic and cook, stirring often, for 30 minutes or until the onions are golden brown. Add the white wine, sherry vinegar and beef broth. Increase the heat to medium-high just to bring to a boil, then reduce the heat to medium-low and cook gently for 30 minutes. Season and finish the soup as directed above.

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Recipe Source

From cookbook author Sara Moulton.

Tested by Bonnie S. Benwick.

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Nutritional Facts

Calories per serving: 420

% Daily Values*

Total Fat: 19g 29%

Saturated Fat: 6g 30%

Cholesterol: 200mg 67%

Sodium: 1010mg 42%

Total Carbohydrates: 39g 13%

Dietary Fiber: 4g 16%

Sugar: 11g

Protein: 18g

*Percent Daily Value based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

Total Fat: Less than 65g

Saturated Fat: Less than 20g

Cholesterol: Less than 300mg

Sodium: Less than 2,400mg

Total Carbohydrates: 300g

Dietary Fiber: 25g

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