Classic Onion Soup Recipe

French Onion Soup is a classic that has stood the test of time. With its rich, caramelized flavors and savory depth, it’s a dish that exudes comfort and sophistication all at once. Originating from France, this soup is a beautiful blend of slow-cooked onions, broth, and melted cheese, making it the perfect starter for any meal or a meal on its own. Whether you’re enjoying it in a Parisian bistro or preparing it in your own kitchen, French Onion Soup offers a warm, hearty, and deeply flavorful experience.

In this guide, we’ll dive into how you can make an authentic French Onion Soup right at home. From gathering your ingredients to serving it up in the most delicious way, you’ll find everything you need to make this timeless dish. But before we jump into the recipe, let’s take a moment to explore the key components and tips that will elevate your soup to restaurant-quality levels.

French Onion Soup isn’t just about throwing a bunch of ingredients into a pot. It’s about patience, technique, and layering flavors. The onions, the star of the dish, need to be slowly caramelized to bring out their natural sweetness, and the broth should be rich and deep. The melted cheese on top forms the final touch, adding creaminess and an irresistible golden crust.

Here’s A Quick Rundown Of The Basic Steps

Caramelize the onions – This is where you develop the flavor. The onions must be cooked slowly over low heat until they turn a beautiful golden brown.
Prepare the broth – Traditionally, this is made from beef stock, but vegetable broth is a great alternative for vegetarians.
Assemble the soup – Once your onions and broth are ready, it’s time to combine everything in a pot.
Top with bread and cheese – A slice of toasted baguette is placed on top, followed by a generous portion of melted Gruyère cheese.
Broil – Pop the soup under a broiler to melt the cheese and create that glorious golden crust.

It sounds simple, but when done right, this soup delivers an unmatched level of comfort. Now, let’s get into the details.

Ingredients Needed

For a classic French Onion Soup, you’ll need:

Onions – The heart and soul of the dish. Yellow onions are the best choice, as they bring out the perfect balance of sweetness and depth when caramelized.
Butter – For sautéing the onions. Adds richness and flavor.
Olive Oil – Used in combination with butter to prevent the butter from burning.
Beef Broth (or vegetable broth) – This is the base of the soup and gives it a robust, savory flavor.
Dry White Wine – Adds acidity to balance the sweetness of the onions and brings complexity to the broth.
Thyme – Fresh thyme adds an herby fragrance and a little earthiness to the soup.
Bay Leaves – Used to infuse the broth with a subtle, aromatic flavor.
Baguette – You’ll need a few slices to top the soup, which will soak up the broth and turn crispy once broiled.
Gruyère Cheese – This cheese is key. It melts beautifully and has a nutty, slightly salty flavor that makes the soup indulgent.
Salt & Pepper – To season the soup to perfection.

Cooking Instructions

Here’s the step-by-step guide to making this mouthwatering soup:

Prepare the onions: Slice 4-5 large yellow onions thinly, aiming for uniform thickness. This helps with even cooking.
Caramelize the onions: In a large, heavy-bottomed pot (preferably a Dutch oven), melt 2 tablespoons of butter with 1 tablespoon of olive oil over medium-low heat. Add the onions and cook them slowly, stirring occasionally. This step takes patience-about 45 minutes to an hour. The goal is to slowly soften the onions and bring out their natural sweetness. Don’t rush this process; it’s worth it. As the onions brown, you can add a pinch of salt to help draw out moisture.
Deglaze with wine: Once the onions have caramelized and are a deep golden brown, pour in 1/2 cup of dry white wine to deglaze the pot. Use a wooden spoon to scrape up any brown bits stuck to the bottom (these bits are packed with flavor). Let the wine cook off for about 2-3 minutes.
Add the broth and herbs: Pour in 4 cups of beef broth (or vegetable broth if you prefer), and add 2-3 sprigs of fresh thyme and 1-2 bay leaves. Bring everything to a simmer and let it cook for another 30 minutes to allow the flavors to meld together. Season with salt and pepper to taste.
Prepare the bread and cheese: While the soup simmers, preheat your broiler. Slice the baguette and toast the slices lightly. Once toasted, sprinkle a generous amount of grated Gruyère cheese on top of each slice. You can add more cheese if you like it extra cheesy!
Assemble and broil: Ladle the hot soup into oven-safe bowls, leaving some room for the bread and cheese. Place a slice of the cheesy baguette on top of each bowl. Put the bowls under the broiler for 3-5 minutes, or until the cheese is melted, bubbly, and golden brown.
Serve and enjoy: Carefully remove the bowls from the oven (they’ll be hot!). Serve the soup immediately, garnished with extra thyme if you like.

Ingredient Insights

Onions: Yellow onions are ideal because they have a perfect balance of sweetness and acidity. While white onions are sharper and red onions are milder, yellow onions create the richest flavor when caramelized.
Butter & Olive Oil: Combining these two fats helps balance richness with a bit of freshness. Butter adds depth, while olive oil keeps it from burning.
Broth: Beef broth is the traditional choice, adding a meaty depth. If you’re going vegetarian or vegan, vegetable broth is a great alternative. Be sure to pick one that’s flavorful, as this is the base of your soup.
Wine: The wine adds acidity, which cuts through the richness of the onions and beef broth, preventing the soup from becoming too heavy.
Cheese: Gruyère is the cheese of choice for French Onion Soup because of its nutty flavor and excellent meltability. It forms a perfect, golden, crispy topping.

Expert Tips

Don’t Rush the Caramelization: The onions need time to develop their deep, sweet flavor. Be patient and let them cook over low heat. Stir frequently to avoid burning, but let the onions slowly release their natural sugars.
Use Quality Broth: The broth is a key ingredient, so using homemade beef broth or a high-quality store-bought option can make a significant difference in the taste.
Toast the Bread Properly: The bread should be toasted until crispy but not too hard. You want it to absorb the broth but still maintain its texture under the melted cheese.
Balance Seasoning: The onions will already bring some sweetness to the soup, so make sure to taste and adjust your seasoning as you go, adding salt, pepper, or even a little balsamic vinegar to deepen the flavor.
Experiment with Cheeses: While Gruyère is the classic, adding a little Swiss or Fontina can introduce a unique twist. You can even mix them for a more complex topping.

Recipe Variations

Vegan French Onion Soup: Skip the butter and use olive oil for caramelizing the onions. Replace beef broth with a high-quality vegetable broth. Use a vegan cheese alternative for the topping (look for one that melts well).
Spicy French Onion Soup: Add a pinch of cayenne pepper or a small diced jalapeño during the caramelization phase to give the soup a spicy kick.
Caramelized Onion Soup with Sherry: Instead of white wine, you can use sherry to deglaze the pot. It adds a different layer of complexity with its nutty, sweet undertones.
Cheese Variations: If you want a stronger flavor, try adding a bit of blue cheese or sharp cheddar to the Gruyère for a bolder topping.

Final Words

French Onion Soup is one of those dishes that truly represents the art of cooking. While the recipe may seem simple on paper, the magic lies in the care and attention you give each step. The sweet, caramelized onions, the rich broth, and the melty cheese all come together to create a truly satisfying dish.

Classic Onion Soup Recipe