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French Onion Soup Recipe

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★★★★★

4.6 from 107 reviews

A classic French Onion Soup recipe that features deeply caramelized onions simmered in a rich beef and chicken broth, finished with a touch of balsamic vinegar and served with toasted, cheese-topped French bread. This comforting soup combines savory, sweet, and tangy flavors, crowned with a bubbly, golden Gruyère and Parmesan crust.

Ingredients

Scale

Soup

  • 4 tablespoons unsalted butter
  • 5 large yellow onions (thinly sliced)
  • 1 teaspoon salt
  • 1 teaspoon granulated sugar
  • 2 cloves garlic (minced)
  • 1/2 cup dry red wine
  • 32 ounces low-sodium beef broth
  • 24 ounces low-sodium chicken broth
  • 1 tablespoon Worcestershire sauce
  • 2 sprigs fresh thyme
  • 1 bay leaf
  • 1/2 tablespoon balsamic vinegar
  • Pinch of salt and freshly ground black pepper (to taste)

Bread & Cheese Topping

  • 5 1-inch thick slices of French bread
  • 2 tablespoons olive oil
  • 1 & 1/2 cups shredded Gruyere Swiss cheese (room temperature)
  • 1/4 cup shredded Mozzarella cheese (room temperature)
  • 2 tablespoons finely grated Parmesan cheese (room temperature)

Instructions

  1. Sauté Onions: In a large pot over medium-high heat, melt the butter. Add the thinly sliced onions and sauté, stirring often, until they soften, about 10 minutes.
  2. Caramelize Onions: Reduce heat to medium, then stir in salt and sugar. Continue cooking the onions for about 35 minutes, stirring every 5 minutes or so, until they are deeply caramelized and almost syrupy in texture.
  3. Add Garlic: Stir in the minced garlic and cook until fragrant, about 20 seconds, taking care not to burn it.
  4. Deglaze with Wine: Pour in the dry red wine to deglaze the pot, scraping up all the flavorful browned bits stuck to the bottom and sides of the pot.
  5. Add Broths and Herbs: Add the low-sodium beef broth, chicken broth, Worcestershire sauce, fresh thyme sprigs, and bay leaf to the pot.
  6. Simmer Soup: Gently simmer the soup over medium to medium-low heat for about 20 minutes, stirring occasionally to meld the flavors.
  7. Remove Herbs: Remove the thyme sprigs and bay leaf, discarding them.
  8. Season Soup: Stir in the balsamic vinegar and taste. Adjust seasoning with additional salt and freshly ground black pepper as needed.
  9. Keep Soup Warm: Reduce heat to low and cover the pot to keep the soup hot while you prepare the bread topping.
  10. Toast Bread: Preheat the oven broiler with the oven rack positioned about 6 inches from the heat source. Arrange the French bread slices on a baking sheet and brush both sides with olive oil. Broil for 2-3 minutes total, flipping once halfway, until the bread is well toasted but not burnt. Keep a close eye on the bread as broiler intensity varies.
  11. Assemble Bowls: Arrange oven-safe bowls or crocks on a rimmed baking sheet. Fill each bowl about two-thirds full with the hot onion soup. Top each bowl with one slice of toasted French bread and sprinkle the Gruyère, mozzarella, and Parmesan cheeses evenly over the bread.
  12. Broil to Melt Cheese: Place the baking sheet under the broiler until the cheese melts, bubbles, and turns golden brown, forming a crusty seal that spills over the sides.
  13. Serve: Carefully remove bowls from the oven and serve immediately to enjoy the rich, cheesy, and savory French Onion Soup.

Notes

  • Use a dry red wine such as Cabernet Sauvignon or Merlot to enhance the flavor profile; avoid sweet wines.
  • Keep a close watch while broiling the bread and cheese to prevent burning.
  • Room temperature cheeses melt more smoothly when broiled.
  • French bread slices should be about 1 inch thick for optimal topping support and toasting.
  • For a vegetarian version, substitute the beef broth with a rich vegetable broth.

Keywords: French Onion Soup, caramelized onions, French bread, Gruyere cheese, beef broth, classic French soup, comfort food

Find it online: https://kitchenbyclara.com/french-onion-soup-recipe/