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Best French Onion Soup

French Onion Soup Recipe

Author: Olivia Ross
A rich and comforting French Onion Soup made with deeply caramelized onions, savory broth, and a gooey three-cheese topping. Perfect for cozy dinners and easy to master at home.
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Prep Time 15 minutes
Cook Time 1 hour 10 minutes
Total Time 1 hour 25 minutes
Course Main Dish
Cuisine French
Servings 5 servings
Calories 378 kcal

Ingredients
  

Soup Base

  • 4 tablespoons unsalted butter
  • 5 large yellow onions thinly sliced
  • 1 teaspoon salt
  • 1 teaspoon granulated sugar
  • 2 cloves garlic minced
  • 32 oz low-sodium beef broth
  • 24 oz low-sodium chicken broth
  • 1 tablespoon Worcestershire sauce
  • 2 sprigs fresh thyme
  • 1 bay leaf
  • ½ tablespoon balsamic vinegar
  • 1 pinch salt and freshly ground black pepper to taste

Topping

  • 5 slices French bread 1-inch thick
  • 2 tablespoons olive oil
  • 1 & ½ cups shredded Gruyere Swiss cheese room temperature
  • ¼ cup shredded Mozzarella cheese room temperature
  • 2 tablespoons finely grated Parmesan cheese room temperature

Instructions
 

  • Melt the butter in a large pot over medium heat. Add the sliced onions and cook until they soften, stirring often. Sprinkle in the salt and sugar, then continue to cook slowly until the onions turn deep golden and syrupy.
  • Stir in the minced garlic and cook briefly until fragrant, keeping the heat moderate.
  • Pour in the beef and chicken broth. Add Worcestershire sauce, thyme, and bay leaf. Let simmer gently to absorb flavors.
  • Remove the thyme and bay leaf. Stir in balsamic vinegar. Taste and adjust seasoning with salt and pepper.
  • Brush bread slices with olive oil and broil until crisp and golden.
  • Ladle soup into oven-safe bowls. Top with toasted bread and cheeses. Broil until cheese melts and turns golden.
  • Let cool slightly and serve hot.

Notes

  • Take your time caramelizing the onions for the richest flavor.
  • Balsamic vinegar replaces the brightness typically added by wine.
  • Let cheese reach room temperature for optimal melt and toast the bread well so it holds up in the broth.
  • Watch carefully while broiling to avoid burning the cheese.

Nutrition

Calories: 378kcalCarbohydrates: 21gProtein: 18gFat: 24gSaturated Fat: 13gCholesterol: 60mgSodium: 1014mgPotassium: 782mgFiber: 3gSugar: 9gVitamin A: 623IUVitamin C: 12mgCalcium: 353mgIron: 1mg
Keyword French Onion Soup
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