Classic French Onion Soup balances an onion's natural sweetness with a savory beef broth creating this rich and comforting dish.
Best Onions for Traditional French Onion Soup
We always find that our favorite soups have a foundation built on simple ingredients, combined to create a symphony of flavors; French onion soup is no exception.
Choosing the right onions is pivotal to the success of this classic French soup.
Yellow Onions with their robust and balanced taste, are traditionally preferred for their ability to mellow out during the long cooking process, allowing their innate sweetness to emerge.
So many chefs, however, swear by the milder, sweeter profile of white onions, which lend the dish a more subtle depth of flavor.
Sweet onions are another popular choice. Their high sugar content guarantees a more pronounced caramelization, which is the heart of this savory broth.
While some recipes may call for red onions, you should keep in mind that their slightly sharper taste might not blend as harmoniously into the cozy soup base.
In the end, the best onions for French onion soup are the ones that simmer slowly to release their sugars, merging with the beef stock to a rich, savory dish that warms you from the inside out.
Mastering Caramelized Onions
The journey to mastering caramelized onions begins with patience and attentiveness.
We use a mix of yellow and sweet onions, which gradually caramelize and contribute to the soup's depth.
The process is not just about browning but coaxing out sugars that lie within each sliver.
Keep your stove on medium heat; too high and the onions will burn, too low and they never develop that rich complexion. Stirring occasionally, watch as they turn a deep golden brown.
The concept is simple: the onions release their moisture and then slowly fry in their own juices, unlocking a symphony of sweetness.
At the perfect moment, a medley of browned bits collects at the bottom of the pan. This is pure gold in terms of flavor, one might say the French onion soup secret ingredient. Pour in a small amount of beef broth and use a wooden spoon to gently scrape off the caramelized treasures.
Following these tips ensures onions that are not just a topping but the soul of your French onion soup.
Ingredients to make French Onion Soup
- Olive Oil and Butter: Used for sautéing the onions, providing flavor, and helping in the caramelization process.
- Onions: The star ingredient. Sliced and caramelized, they give the soup its sweet and savory taste.
- Salt: Enhances the overall flavor of the soup.
- Bay Leaf and Fresh Thyme: Adds aromatic depth to the soup. The bay leaf and thyme infuse their flavors during cooking.
- Garlic: Adds a savory element and complements the sweetness of the caramelized onions.
- All-Purpose Flour: Used as a thickening agent for the soup.
- Sugar: Enhances the caramelization of the onions, adding sweetness to balance the flavors.
- Beef Broth: The base of the soup, providing a rich and savory taste. Low sodium is preferred to control the overall saltiness.
- Black Pepper: Adds a hint of spiciness and complements the sweetness of the onions.
- Sourdough Baguette: Sliced and toasted to create the classic topping for French Onion Soup. It adds texture and absorbs the flavorful broth.
- Gruyere and Mozzarella Cheese: The melted cheese topping is a signature element of French Onion Soup, providing a gooey and savory finish.
How to make Classic French Onion Soup
After your onions achieve a deep golden brown hue from carmelizing, start layering flavors to give your French onion soup its distinct, savory character.
Allow the soup to simmer patiently.
Cheesy, Toasty Toppings
Start by preheating your oven's broiler to get ready for what might just be the crowning glory of our French onion soup: the cheesy, toasty topping.
On a baking sheet, arrange the baguette slices in a single layer, careful not to overlap. Each piece will become the base for a generous amount of grated Gruyere and mozzarella cheese.
Sprinkle the cheese evenly across all the slices. This blend promises a melt with both excellent flavor from the Gruyere and a beautiful stretch from the mozzarella.
Under the broiler they go, just for a minute or two. Keep a close eye on them, watching for the cheese to melt and bubble, turning a delightful golden brown at the edges.
The final product is a cheesy toast that once topped on a steaming bowl of French Onion Soup will create that classic comforting experience.
Frequently Asked Questions
Can I use vegetable broth instead of beef broth for a vegetarian version?
Yes, you can substitute vegetable broth for beef broth to make a vegetarian French Onion Soup. The flavor will be different but still delicious.
Do I have to use Gruyere and mozzarella cheese, or can I choose other types?
Gruyere and mozzarella are traditional choices, but you can experiment with other melting cheeses like Swiss or provolone. Choose cheeses with good melting properties and complementing flavors.
Can I make French Onion Soup in advance?
Yes, you can make the soup ahead of time. Store the soup and bread separately, and assemble and broil with cheese just before serving to maintain the bread's texture.
Can I freeze French Onion Soup?
While the soup can be frozen, keep in mind that the texture of the onions may change slightly upon thawing. It's best enjoyed fresh, but freezing is an option if needed.
Classic French Onion Soup Recipe
- 1 tablespoon olive oil
- 4 tbsps unsalted butter
- 2 lbs onions halved and thinly sliced
- ½ teaspoon salt
- 1 bay leaf
- 2 sprigs fresh thyme
- 4 cloves garlic minced
- 1 tablespoon all-purpose flour
- 1 teaspoon sugar
- 4 cups beef broth preferably low sodium
- black pepper to taste
- 1 small sourdough baguette sliced
- ¼ lb Gruyere cheese grated
- ¼ lb mozzarella cheese
- Heat a dutch oven or a heavy pan over medium-high heat.
- Add the olive oil and butter. When the butter has melted, add the onions, stirring to coat with the fat.
- Reduce heat to medium-low, cover and cook for about 10 minutes to soften them and to help bring out some of the moisture, stirring several times.
- Add the sugar and salt and continue cooking, stirring often so the onions brown evenly.
- Cook until the onions are a rich brown color, about 30-40 minutes more.
- Add the garlic, bay leaf and fresh thyme and cook for 1-2 minutes. Discard the bay leaf and thyme sprigs.
- Now add the flour, stir and cook for 2 minutes.
- Add the beef broth, bring to a boil, reduce heat and simmer for 8-10 minutes or until reduced slightly.
- Adjust seasoning with salt and black pepper.
- Preheat your oven. Arrange the baguette slices on a baking sheet. Remember not to overcrowd.
- Top the slices with cheese and broil until it melts and begins to brown-around 1-2 minutes.
- To serve, ladle into bowls and top with a crispy cheesy toasted baguette slice
- Serve hot and enjoy!!