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This is a simple and basic French onion soup made with beef stock and sliced caramelized onions. The soup is broiled briefly to melt the Gruyère cheese on the toasted French bread.
It’s a traditional soup with caramelized onions and beef stock. Just before serving, a slice of toasted baguette and a generous amount of Gruyère cheese is placed on each bowl of soup and broiled until melted and browned. Caramelizing the onions takes a bit of time, but all-in-all, it’s a very easy preparation.
What You’ll Like About This Recipe
Deep flavor from simple ingredients. The long, slow caramelization of onions creates layers of sweetness and savoriness without relying on wine, brandy, or extra seasonings. The result is a soup that tastes rich and complex using pantry staples.
Clear, approachable technique. This recipe focuses on the essential steps—properly cooking the onions, building the broth, and finishing under the broiler—making it easy to understand why each step matters and how it affects the final dish.
Balanced richness. Using both oil and butter prevents burning while adding flavor, and a small amount of cornstarch gives the broth body without making it heavy or stew-like.
Classic presentation. Toasted bread and melted Gruyère create the signature French onion soup topping, offering contrast between the savory broth, soft onions, crisp bread, and gooey cheese.
Flexible and forgiving. The soup can be adjusted to taste, scaled up for guests, or made ahead, making it practical as well as satisfying.
Comforting but not fussy. This is a soup that feels special without being complicated, perfect for cooks who appreciate traditional flavors and straightforward methods.
Ingredient Notes
- Onions – The star of the soup. Cooking them slowly allows their natural sugars to caramelize, creating sweetness and depth that define the dish.
- Vegetable oil and butter – Oil raises the smoke point while butter adds flavor, helping the onions brown evenly without scorching.
- Cornstarch – A small amount lightly thickens the broth, giving it a silky texture without masking the onion flavor.
- Beef stock – Provides a savory foundation that balances the sweetness of the onions; unsalted stock allows better control over seasoning.
- Kosher salt and black pepper – Essential for sharpening flavors and keeping the soup from tasting flat.
- French bread – Thick slices toast well and hold up under the cheese and broth.
- Gruyère cheese – Nutty, salty, and highly meltable, it creates the classic bubbly topping associated with French onion soup.
How to Make the Recipe
- Cook the onions slowly in oil and butter until soft, golden, and deeply caramelized.
- Stir in the cornstarch until the onions are evenly coated.
- Gradually add the stock and simmer until the flavors meld and the broth develops body.
- Ladle the soup into oven-safe bowls and top with toasted bread and cheese.
- Broil until the cheese is melted, bubbly, and lightly browned.
Pro Tips
- Take your time with the onions; proper caramelization builds flavor and sweetness that can’t be rushed.
- Lower the heat and add a splash of water if the onions begin to stick, scraping up browned bits for extra flavor.
- Toast the bread before topping so it stays structured under the cheese.
- Place bowls on a baking sheet when broiling to make them easier and safer to handle.
- Watch closely under the broiler, as the cheese can brown quickly.
Recipe Variations
- White wine French onion soup. Deglaze the onions with dry white wine before adding stock to introduce acidity and depth that brighten the finished soup.
- Brandy or sherry version. A small splash added after caramelizing the onions brings warmth and complexity without overpowering the onions.
- Chicken stock adaptation. Using chicken stock creates a lighter soup that still highlights the sweetness of the onions.
- Herb-infused soup. Simmer with thyme, bay leaf, or a small bundle of fresh herbs for subtle aromatic notes.
- Vegetarian French onion soup. Use a rich vegetable stock and increase the onions slightly to maintain body and flavor.
- Cheese-forward topping. Combine Gruyère with Swiss or Comté for a more pronounced cheese layer and varied melt.
- Gluten-free option. Skip the bread topping or use gluten-free bread, keeping the soup base naturally gluten-free.
Serving Suggestions
- Serve as a starter for a French-inspired meal or as a light main course.
- Pair with a crisp green salad to balance the richness.
- Add a glass of dry white wine to complement the sweet onions.
- Choose simple accompaniments so the soup remains the focal point.
How to Store
Refrigerate. Cool completely and store the soup base in an airtight container for up to 3 to 4 days. Keep bread and cheese separate.
Freeze. Freeze the soup base without bread or cheese in freezer-safe containers for up to 3 months. Label and thaw overnight in the refrigerator.
Reheat. Reheat gently on the stovetop until hot, then add bread and cheese and broil just before serving.
Frequently Asked Questions
Basic French Onion Soup
Ingredients
- 2 large onions, sliced
- 2 tbsp vegetable oil
- 1 tbsp unsalted butter
- 1 tbsp cornstarch
- 5 cups beef stock, preferably unsalted
- kosher salt and freshly ground black pepper, to taste
- 6 slices French bread, thick slices toasted
- 1 cup Gruyere cheese, shredded
Instructions
- Place a Dutch oven or large saucepan over medium heat. Heat the vegetable oil and butter until the butter has melted. Add the onions and cook until soft and caramelized, stirring frequently. This will take about 15 to 20 minutes. Turn the heat down and add a splash of water if the onions begin scorching or sticking to the pan.
- Add the cornstarch and stir until well blended. Gradually add the beef stock. Taste and add salt and pepper, as needed. Bring to a boil. Reduce the heat to low and simmer, uncovered, for about 20 to 30 minutes.
- Preheat the broiler.
- Ladle the soup into oven-safe bowls. Place a slice of toasted French bread on each serving and top with a generous amount of shredded cheese.
- Place the bowls on a baking sheet and broil just until the cheese is melted and bubbly.
Nutrition
Disclaimer:
Our nutritional information is based on a third-party application that analyzes the ingredients list to determine the values. The information is meant to be helpful, but should be considered an estimate. Values may differ depending on measurements, brands, serving variations, and database availability.
