Description
This classic French Onion Soup recipe features deeply caramelized onions simmered in a rich homemade beef broth infused with fresh herbs and a touch of sherry. Topped with toasted French bread slices and a blend of melted Gruyere, Parmesan, and Swiss cheeses, this comforting soup is perfect for warming up on a chilly day.
Ingredients
Scale
Onions and Seasoning
- 4 large yellow onions (about 3 pounds, thinly sliced)
- 1 tablespoon kosher salt (use less if you have table salt)
- 1/4 teaspoon cayenne pepper (optional)
- 4 tablespoons butter (half stick)
- 2 tablespoons all purpose flour
- 1/2 cup sherry wine (or white wine)
- 1 tablespoon fresh lemon juice (about half a lemon)
Broth and Vegetables
- 8 cups high quality beef broth (Brodo brand or Kettle and Fire recommended)
- 2 cups water
- 1 tablespoon Better Than Bouillon Beef Base
- 3 carrots (peeled and roughly chopped)
- 1 yellow onion (roughly chopped)
- 2 stalks celery (roughly chopped)
- 6 large cloves garlic (smashed)
- 1 teaspoon prepared horseradish
- 3 sprigs fresh thyme (or 1/2 teaspoon dried thyme)
- 3 small sprigs fresh rosemary (or 1/2 teaspoon dried rosemary)
- 3 bay leaves
- 15 peppercorns (about 1/2 teaspoon)
Bread and Cheese Toppings
- 1 (1-pound) loaf of French Bread (sliced into 1-inch slices)
- 1 cup Gruyere cheese (freshly grated)
- 1 cup Parmesan cheese (freshly grated)
- 8 ounces Swiss cheese (sliced)
- Optional: Butter for toasting bread
- Freshly chopped chives (for garnish)
- Cracked black pepper (for garnish)
Instructions
- Slice Onions: Start by thinly slicing 4 large yellow onions to yield about 8 cups. Thin slices ensure tenderness and ease of eating in the finished soup.
- Sauté Onions: In a 12-inch, high-sided stainless steel pan, melt 4 tablespoons of butter over medium heat. Add all the onions, sprinkle with 1 tablespoon kosher salt, and add 1/8 to 1/4 teaspoon cayenne pepper if using.
- Cook Onions Until Transparent: Stir occasionally and cook the onions over medium heat for about 10 minutes until they become translucent.
- Caramelize Onions Low and Slow: Reduce heat to medium-low and let the onions cook for about 90 minutes, stirring every 10-20 minutes to ensure even cooking and prevent burning. They will gradually turn golden and develop a sweet, umami flavor.
- Prepare Broth: In a large Dutch oven or stockpot, bring 8 cups beef broth, 2 cups water, and 1 tablespoon Better Than Bouillon Beef Base to a boil over high heat.
- Add Vegetables and Herbs: Add carrots, chopped onion, celery, smashed garlic, horseradish, thyme, rosemary, bay leaves, and peppercorns to the broth.
- Simmer Broth: Reduce heat to low and simmer with a vented lid, allowing some steam to escape, while the onions caramelize.
- Strain Broth: After onions are caramelized, strain the broth through a colander into a large bowl, discarding the vegetables (though the cooked carrots can be eaten). Return broth to the pot and keep warm.
- Check Onion Flavor: Taste the onions; they should have a deep, sweet, and complex flavor without bitterness. Continue caramelizing if flavor is flat.
- Add Flour to Onions: Sprinkle the onions with 2 tablespoons flour, stirring for 1-2 minutes to incorporate and cook off the raw flour taste.
- Deglaze with Sherry: Pour in 1/2 cup sherry wine (or white wine), turn heat to medium, and stir thoroughly, scraping browned bits from the pan.
- Add Lemon Juice: Stir in 1 tablespoon fresh lemon juice and continue cooking until most liquid is absorbed and pan is smooth.
- Combine Onions and Broth: Transfer caramelized onions into the broth pot, stir well, and taste. Adjust seasoning with salt, horseradish, or thyme as desired.
- Prepare Bread: Preheat oven to 350°F. Slice French bread into 1-inch pieces and lay on a baking sheet. Optionally butter each slice.
- Toast Bread: Bake bread slices for 10 minutes until crisp on top, then flip and toast an additional 5 minutes until golden and toasted on both sides.
- Prepare Serving Bowls: Grate Parmesan and Gruyere cheeses. Sprinkle about 1/2 tablespoon of each cheese in the bottom of 7 oven-safe bowls.
- Ladle Soup: Pour soup evenly into the bowls placed on a half baking sheet for easy transfer.
- Add Bread and Cheese Toppings: Place one toasted bread slice on each bowl, then sprinkle with 1/2 tablespoon grated Gruyere and Parmesan each, and finally top with a slice of Swiss cheese.
- Broil Cheese: Move oven rack to upper third, set broiler to high, and broil the bowls for 2-4 minutes until cheese is melted and beginning to brown.
- Serve Carefully: Remove soup from oven using hot pads, warn guests the bowls are hot, and garnish with freshly chopped chives and cracked black pepper.
- Storage: Store leftover soup in airtight containers in the refrigerator for 4-5 days, keeping bread and cheese separate.
- Freezing: Soup can be frozen; keep bread and cheese separate for best texture.
Notes
- Use a high-quality beef broth for the best flavor impact.
- Caramelizing onions low and slow is key for deep flavor and sweetness without bitterness.
- Sherry wine adds dimension, but white wine works if preferred.
- French bread is traditional; toasting helps it hold up well under the melted cheese.
- Use oven-safe bowls to broil the soup safely.
- Adjust seasoning at the end because caramelization can intensify sweetness.
- Keep bread and cheese separate when storing leftovers to avoid sogginess.
- Horseradish adds a subtle spicy depth but can be adjusted to taste or omitted.
- Consider garnishing with fresh chives for color and mild onion flavor.