Classic French Onion Soup
A timeless French Onion Soup featuring slowly caramelized onions and cheesy toasted bread, delivering rich flavors and comforting warmth. The recipe balances depth of taste with approachable steps, making it perfect for everyday cooking or special occasions.
Equipment
- 1 heavy-bottomed casserole pot
- 1 Ladle
- 1 grill/broiler rack
- 1 Sharp Chef’s Knife
- 1 Wooden Spoon
Ingredients
For the Soup:
- 100 g unsalted butter
- 1.25 kg brown or yellow onions peeled, halved, and thinly sliced from top to bottom
- 185 ml dry white wine optional
- 2 tablespoons all-purpose flour
- 1.5 liters good-quality beef or chicken broth preferably low-sodium
- 2 dried bay leaves or 3 fresh bay leaves optional
- 3 fresh thyme sprigs optional
- Salt and freshly ground black pepper to taste
For the Cheesy Toast:
- 6 to 8 slices of French baguette or a soft bread of your choice
- 100 g Gruyère mozzarella, or any good melting cheese
- Fresh parsley or thyme leaves for garnish optional
Instructions
- Slowly Soften the Onions: In a heavy-bottomed pot, melt the butter over medium heat until it begins to foam. Add the sliced onions, stirring well to coat them evenly with the butter. Lower the heat to medium-low and cook the onions gently for about 30 minutes. Stir occasionally to ensure they soften evenly and become translucent.
- Deepen the Onion Flavor: Turn the heat up to medium or medium-high and sprinkle in a pinch of salt. Continue cooking for another 20 to 30 minutes, stirring frequently. This step will caramelize the onions slowly, turning them golden brown and releasing their natural sweetness and rich flavor.
- Add Wine to Deglaze: Pour in the white wine to deglaze the pot, scraping the bottom to lift any browned bits. Let the wine simmer and reduce for about 2 minutes until mostly evaporated, enriching the base of your soup.
- Incorporate Flour: Sprinkle the flour evenly over the caramelized onions and stir continuously for 1 minute. This will help thicken the soup gently without clumping.
- Add Broth and Herbs: Pour in the broth, then add the bay leaves and thyme sprigs. Bring the mixture to a gentle simmer. Cover the pot, reduce heat to low, and allow it to simmer softly for 30 minutes to marry the flavors.
- Prepare the Cheesy Toast: While the soup simmers, preheat your grill or broiler on high. Toast the bread slices on both sides until lightly golden. Place cheese slices on the toasted bread, then return under the grill until the cheese melts fully and develops golden spots.
- Final Seasoning and Serving: Remove the bay leaves and thyme sprigs from the soup. Taste and adjust seasoning with salt and pepper as needed. Ladle the hot soup into bowls, then float one or two cheesy toast slices on top. Garnish with fresh parsley or thyme if desired, and serve immediately.
Notes
- Onion Slicing Tip: Cutting onions from top to bottom helps them retain shape and avoid stringy bits during cooking, but feel free to slice as preferred.
- Wine Substitution: White wine adds depth and assists deglazing but can be omitted without compromising the overall flavor.
- Broth Choice: For best flavor, use a high-quality beef broth. If unavailable, chicken broth is a good substitute. Avoid low-quality store-bought broths for best results.
- Bread Selection: Choose a soft crumb bread like French baguette or sandwich bread to ensure it soaks up the soup and is easy to cut with a spoon. Avoid hard or dense artisan breads like sourdough.
- Slow Cooker Option: Caramelize onions in a slow cooker on low for 10 hours with butter, then finish in a pot over medium-high heat for 10–15 minutes to deepen flavor before proceeding with the recipe.