Rich, cheesy French onion soup is one of the coziest classic soups, and this lighter adaptation delivers the same deep, comforting flavor with fewer calories. Sweet, slowly caramelized onions simmer in a savory beef broth brightened with a splash of wine and brandy, then finished with toasted bread and melted cheese for a satisfying bowl any night of the week.
The Best French Onion Soup Recipe
I love ordering French onion soup at our neighborhood bistro, but restaurant portions can be indulgent. I developed this version to capture the authentic, beefy flavor while trimming unnecessary calories. It’s straightforward to make and perfect for cold evenings when you want a warming, savory meal. I often rotate this alongside other favorite winter soups.
Reasons to Love This French Onion Soup
When the temperature drops I turn to easy, comforting soups. This French onion soup stands out for a few reasons:
- Authentic depth of flavor. To keep the profile rich without excess calories, the soup uses dry sherry, white wine, and a touch of Cognac or brandy for complexity.
- Cheesy, but not overdone. Instead of piling on cheese, this recipe uses one slice per serving. Gruyère is traditional, but reduced-fat Swiss (such as Alpine Lace) is a lighter alternative that still melts beautifully.
- Just enough butter. Caramelizing onions requires fat for flavor and texture, but this recipe keeps it modest—about two tablespoons—so the soup tastes indulgent without being heavy.
Ingredients You’ll Need
Below are the ingredients used in this lighter French onion soup. Exact measurements appear in the recipe card further down.
- Onions: Yellow onions are classic; Vidalia, white, or red onions will also work.
- Unsalted butter: Adds richness; you can substitute olive oil if preferred.
- Flour: A small amount creates a roux to slightly thicken the broth; use a gluten-free flour if needed.
- Bay leaf and dried thyme: Aromatics that enhance the soup’s depth.
- Dry sherry, white wine, and Cognac or brandy: These boost flavor. If you avoid alcohol, replace with extra broth and a splash of balsamic or sherry vinegar for acidity.
- Beef broth: Store-bought or homemade—good-quality broth makes a real difference.
- Crusty bread: Toasted Italian bread, baguette, or sourdough holds up well as a topper.
- Cheese: Traditionally Gruyère; reduced-fat Swiss is a lighter alternative that melts well.
How to Make French Onion Soup
This recipe takes a bit of time to caramelize the onions, but the steps are simple. Follow the recipe card below for exact measurements and printable instructions.
- Caramelize the onions. In a large pot or Dutch oven, sauté sliced onions in butter over medium heat until soft and deeply caramelized, about 20–30 minutes. Add a splash of water if they begin to stick or dry out.
- Add flour and aromatics. Stir in the flour and cook 2–3 minutes. Add thyme, bay leaf, sherry, white wine, and Cognac or brandy, then simmer uncovered for 10 minutes to reduce and concentrate the flavors.
- Simmer with broth. Pour in the beef broth, season with salt and pepper, reduce heat, cover, and simmer gently for 20 minutes. Remove the bay leaf before serving.
- Assemble bowls. Ladle the soup into oven-safe bowls placed on a baking sheet. Add toasted bread to each bowl and top with a slice of cheese.
- Broil until melted. Broil 2–3 minutes until the cheese is melted and bubbly. Watch closely to prevent burning.
Tips and Variations
A few practical tips and easy variations to customize this soup.
- Use good-quality broth: Homemade beef stock adds the richest flavor, but choose a canned broth you enjoy if you prefer convenience. You can also blend half beef and half chicken broth for a lighter taste.
- Low-carb options: Replace the bread with steamed cauliflower florets or crisp Parmesan tuiles to hold the melted cheese.
- Gluten-free version: Use gluten-free flour for the roux and gluten-free bread for the topping.
- Cheese swaps: Gruyère is classic, but fontina, provolone, or mozzarella are tasty alternatives if you prefer.
- Make ahead: The broth and cooked onions can be prepared up to 4 days ahead. Reheat, then add toast and cheese and broil just before serving.
What to Serve With French Onion Soup
French onion soup is hearty on its own but pairs beautifully with light salads or roasted mains. Try a simple arugula salad, a pear-and-Gorgonzola autumn salad, or a green salad with shaved Parmesan to keep the meal balanced.
Proper Storage
- Refrigerator: Store cooled soup in an airtight container for up to 4 days.
- Freezer: Freeze the soup without bread and cheese for up to 3 months. Thaw overnight in the refrigerator before reheating.
- To reheat: Warm the soup gently on the stovetop until simmering, then ladle into oven-safe bowls, add toasted bread and cheese, and broil until the cheese melts.
More Soup Recipes You’ll Love
- Classic Potato Leek Soup
- Kale and Potato Soup with Turkey Sausage
- Chicken Noodle Soup
- Cream of Asparagus Soup
- Golden Red Lentil Soup with Spinach
French Onion Soup
Yield: 6 servings
Serving size: 1 to 1 1/2 cups
Prep: 5 mins • Cook: 55 mins • Total: ~1 hr
Calories: 312.8 kcal per serving
Ingredients
- 2 pounds yellow onions, thinly sliced
- 2 tbsp unsalted butter
- 2 tbsp flour (or gluten-free flour)
- 1 bay leaf
- 1/2 tsp dried thyme
- 1 ounce dry sherry
- 1 ounce Cognac or brandy
- 2 ounces white wine
- 9 cups beef broth (store-bought or homemade)
- Kosher salt and freshly ground pepper, to taste
- 6 slices toasted Italian bread (about 6 ounces) or gluten-free bread
- 6 slices reduced-fat Swiss or your preferred cheese
Instructions
- In a Dutch oven or large pot, sauté the sliced onions with the butter over medium heat until soft and golden, about 20–30 minutes, stirring often. Add a few drops of water if they become too dry. Aim for deep caramelization without burning.
- Stir in the flour and cook for 2–3 minutes to form a light roux.
- Add the thyme, bay leaf, sherry, white wine, and Cognac or brandy. Simmer uncovered for 10 minutes to allow the alcohol to reduce and flavors to meld.
- Pour in the beef broth, season with salt and pepper, reduce the heat, cover, and simmer gently for about 20 minutes. Remove the bay leaf.
- Ladle about 1 to 1 1/2 cups of soup into each oven-safe bowl. Place a slice of toasted bread into each bowl and top with a slice of cheese.
- Place the bowls on a baking sheet and broil for 2–3 minutes, until the cheese is melted and bubbly. Serve hot and enjoy.
Nutrition (per serving)
Calories: 312.8 kcal • Carbs: 31.6 g • Protein: 17.9 g • Fat: 11 g • Fiber: 3.3 g • Sodium: 875 mg • Sugar: 4.8 g