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Classic French Onion Soup Recipe

This delicious classic French Onion Soup recipe with slowly caramelized onions is served with Crostini’s and Gruyere cheese.

Prep Time
30 mins
Cook Time
2 hrs
Total Time
2 hrs 30 mins
Servings: 8
Calories: 674 kcal
Course: Soup
Cuisine: French

Ingredients

  • 3 ounces unsalted butter
  • 4 peeled and thickly sliced yellow onions
  • 4 peeled and thickly sliced white onions
  • 1 ½ tablespoons sugar
  • 6 finely minced cloves of garlic
  • 2 cups of red wine
  • 12 cups beef stock
  • 2 tablespoons chopped fresh thyme
  • 2 tablespoons balsamic vinegar
  • 16 crostinis
  • 4 cups shredded gruyere cheese
  • sea salt and fresh cracked pepper to taste

Instructions

    Cup of Yum
  1. Heat the butter over low heat in a large pot until melted.
  2. Add the onions and caramelize them very well while occasionally stirring, which can take up to an hour.
  3. Halfway through the cooking process, you can add in some sugar to help brown and add more sweetness. This will be heavily scrutinized. Sugar makes caramel, so it’s kind of the same thing in this soup. Sometimes you may find that your onions aren’t getting sweet maybe because of the way that specific batch is and you may need some sugar.
  4. Once caramelized, add in the garlic and sweat for 3 to 4 minutes.
  5. Next, de-glaze with red wine and cook the liquid until it is mostly absorbed into the onions. This process is known as “au sec.”
  6. Next, add the beef stock and simmer for at least 20 minutes.
  7. Finish with fresh thyme, salt, and pepper, and adjust with balsamic vinegar.
  8. Pour the soup into an oven-safe bowl and top off with a few crostini’s and add at least ½ cup to 1 cup of shredded gruyere cheese.
  9. Place the soup on a sheet tray and cook it under the broiler on high for 3 to 4 minutes or until the cheese is browned and melted.

Notes

  • Make-Ahead: You can make this French onion soup up to 1 day ahead of time, just follow the reheating instructions below.
  • How to Store: You can store this covered in the refrigerator for 4 to 5 days. This will also freeze covered for up to 6 months. Thaw in the refrigerator before reheating and serving. 
  • How to Reheat: Add the desired amount of onion soup to a medium-sized saucepot and cook over low heat until hot. Adjust the seasonings with salt and pepper and serve.
  • If you are finding that your onions are not browning, you can turn the heat up slightly while frequently stirring.
  • We used to make a 5-onion soup at a different restaurant I worked at where we used white, yellow, red, leeks and garlic and then topped off with a bleu cheese crouton. In addition, we would add cream to this soup during the wintertime. Feel free to get creative.
  • Feel free to add more cheese to the crostini before baking.

Nutrition Information

Calories 674kcal (34%) Carbohydrates 51g (17%) Protein 34g (68%) Fat 32g (49%) Saturated Fat 18g (90%) Polyunsaturated Fat 2g Monounsaturated Fat 9g Trans Fat 0.3g Cholesterol 95mg (32%) Sodium 1589mg (66%) Potassium 1062mg (30%) Fiber 4g (16%) Sugar 13g (26%) Vitamin A 978IU (20%) Vitamin C 12mg (13%) Calcium 808mg (81%) Iron 4mg (22%)

Nutrition Facts

Serving: 8Serving

Amount Per Serving

Calories 674

% Daily Value*

Calories 674kcal 34%
Carbohydrates 51g 17%
Protein 34g 68%
Fat 32g 49%
Saturated Fat 18g 90%
Polyunsaturated Fat 2g 12%
Monounsaturated Fat 9g 45%
Trans Fat 0.3g 15%
Cholesterol 95mg 32%
Sodium 1589mg 66%
Potassium 1062mg 23%
Fiber 4g 16%
Sugar 13g 26%
Vitamin A 978IU 20%
Vitamin C 12mg 13%
Calcium 808mg 81%
Iron 4mg 22%

* Percent Daily Values are based on a 2,000 calorie diet.