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Rich, cheesy French onion soup is one of my favorite cozy soup recipes, and this easy lightened-up version is just as delicious as the original! It’s packed with caramelized onions in a warm, beefy broth, topped with crusty bread and melted cheese.

French onion soup in ramekins topped with toast and melted cheese, garnished with thyme sprigs.

The Best French Onion Soup Recipe

We love going to our neighborhood restaurant for French onion soup, but it’s far from light. I wanted to recreate their soup at home so I could enjoy it more often, but with fewer calories. This French onion soup is easy to make and lighter than most restaurant versions. A hearty bowl is the perfect meal this time of year when it’s so cold outside. I don’t know about you, but for me, I’ve got all my favorite Cozy Soup Recipes on frequent rotation in the winter!

Reasons to Love This French Onion Soup Recipe

Once the colder weather arrives, I’m all about easy, comforting soup recipes like Beef Barley Soup, creamy Chicken and Mushroom Soup, and Stuffed Pepper Soup, along with classic French onion. There are a lot of French onion soup recipes out there, but here’s why this one is my favorite!

Authentic flavor. While lightening up this recipe, I still wanted it to taste authentic, so I’ve made it with dry sherry, white wine, and cognac to add lots of depth to the flavor.
Cheesy without overdoing it. Traditional French onion soup is topped with lots of cheese. While it’s delicious, it’s not the healthiest. My recipe calls for just one slice of cheese on each serving. Gruyere cheese is typically used in French onion soup, but Alpine Lace Swiss cheese is a great lighter alternative.
Just enough butter. Another difference between traditional French onion soup and my version is that it usually uses a lot more butter. I’ve found that 2 tablespoons is the perfect amount.

Sliced onions being stirred in a pot by a wooden spoon.

Ingredients You’ll Need

Here are all the ingredients needed to make this light French onion soup recipe. See the recipe card below for the exact measurements.

Yellow onions, or you could use Vidalia, white, or red onions.
Unsalted butter: You can substitute olive oil if you prefer, but I like the richness that butter adds.
Flour creates a roux when combined with the melted butter, and helps thicken the soup.
Bay leaf and dried thyme both add flavor to this soup.
Dry sherry: If you don’t cook with alcohol, you can use extra broth instead (for this and the next 2 ingredients as well), but I’d suggest adding a splash of balsamic vinegar or sherry vinegar for some depth.
Cognac is my favorite addition to French onion soup, but brandy works too.
White wine, like Sauvignon Blanc, Pinot Grigio, or another dry white wine are all great options.
Beef broth, either store-bought or homemade.
Bread: I like to use toasted Italian bread. Any crusty, sturdy bread, like French baguette or sourdough, works well as a topper for French onion soup.
Reduced-fat Swiss, like Alpine Lace, makes a great, lighter stand-in for traditional Gruyere cheese.

How to Make French Onion Soup

While it does take a bit of time to caramelize the onions, this recipe is very easy. See the recipe card below for printable instructions.

Caramelized onions in a large pot. — Caramelize the onions.

French onion soup topped with a slice of toasted bread in a ramekin. — Caramelize the onions.

Caramelize the onions. Cook the onions with the butter in a large pot until they’re caramelized—this will take 20 to 30 minutes. If needed, add a splash of water to keep them from getting dry.
Add the next few ingredients. Stir in the flour for 2 to 3 minutes, then add the herbs, sherry, wine, and brandy. Simmer uncovered for 10 minutes.
Continue to simmer. Pour in the beef broth and season with salt and pepper. Reduce the heat, cover, and simmer for 20 minutes.
Divide into bowls. Remove the bay leaf and ladle the soup into oven-proof bowls set on a baking sheet. Place toasted bread slices into the soup, then top with cheese.
Broil. Place the baking sheet in the oven and broil for 2 to 3 minutes, or until the cheese melts. Keep an eye on it, as the cheese can burn quickly if left under the broiler for too long.

Overhead view of French onion soup in ramekins.

Tips and Variations

Here are some tips and variations I’ve come up with over the years of making this French onion soup.

Use a good beef stock: I usually make my own, which makes all the difference in flavor, but canned works fine too, as long as you use one you really like. This Best Beef Broth and Stock article from Epicurious is helpful. I’ve also done this with half beef and half chicken broth.
Make it low-carb: You can make this soup low-carb by swapping the bread for steamed cauliflower to hold the cheese. Another low-carb trick I like to use is making Parmesan crisps (without the everything bagel seasoning) and using that to hold the cheese when melting.
Make it gluten-free: Replace the flour and bread with gluten-free alternatives to make gluten-free French onion soup.
Swap out the cheese: Use Gruyere or another white cheese, such as fontina, mozzarella, or provolone, instead of the reduced-fat Swiss if you prefer.
Meal prep it: The broth can be made ahead and refrigerated for up to 4 days. Reheat on the stove, then toast the bread and melt the cheese before serving.

Overhead view of a spoon resting in a bowl of French onion soup.

What to Serve With French Onion Soup

Serve French onion soup alongside any of the following easy dishes.

Proper Storage

Refrigerator: Store French onion soup in an airtight container for up to 4 days.
Freezer: You can freeze the soup without the cheese and bread for up to 3 months. Thaw in the refrigerator before reheating.
To reheat: Place the soup in a pot and warm it up over medium heat until it starts to simmer. Simmer for a few minutes, then divide it into bowls, add the bread and cheese, and broil as directed.

French Onion Soup Recipe