Ingredients You’ll Need
For the Caramelized Onions
- Yellow onions: These are the best everyday choice because they become sweet, golden, and rich as they cook down.
- Butter: Adds classic flavor and helps the onions soften into a silky texture.
- Olive oil: Helps prevent the butter from browning too quickly while the onions cook slowly.
- Salt: Draws moisture from the onions and helps them soften evenly.
- Sugar, optional: A tiny pinch can help encourage caramelization, especially if your onions are not very sweet.
For the Soup Broth
- Beef broth: Gives the soup deep, savory flavor. Use a good-quality broth because it is the foundation of the recipe.
- Chicken broth, optional: You can use a mix of beef and chicken broth for a slightly lighter flavor.
- Garlic: Adds warmth and depth after the onions caramelize.
- Dry white wine, optional: Adds brightness and helps lift the browned flavor from the pot. You can replace it with extra broth.
- Worcestershire sauce: Adds savory depth and makes the broth taste richer.
- Bay leaf and thyme: These herbs give the soup a classic cozy aroma.
- Black pepper: Balances the sweetness of the onions.
For the Melty Cheese Topping
- Baguette slices: Toasted bread creates the base for the melted cheese and soaks up the broth beautifully.
- Gruyère cheese: The classic choice for French onion soup because it melts beautifully and has a nutty flavor.
- Swiss cheese: A great substitute if Gruyère is not available.
- Parmesan cheese: Adds salty flavor and helps create a golden top.
Substitution Tips
If you do not want to use wine, replace it with extra beef broth and a small splash of apple cider vinegar or lemon juice for brightness. If you cannot find Gruyère, use Swiss, provolone, mozzarella, or a mix of cheeses that melt well.
For a vegetarian version, use a rich vegetable broth and add a little soy sauce or Worcestershire-style vegetarian sauce for depth. For a lighter version, use less cheese on top and serve with a fresh green salad.
