French Onion Soup is a timeless classic that wraps you in layers of rich, caramelized sweetness and savory depth. Slowly simmered for over two hours, the onions transform into a golden, velvety base that’s both comforting and luxurious. Topped with a crusty, toasted baguette and melted Gruyère cheese, every spoonful offers a perfect balance of gooey, crunchy, and tender textures. This soup is a celebration of patience and flavor, making it worth every minute of preparation.
Each bowl is a hearty, soul-warming experience, packed with 26g of protein and a medley of nutrients. The aromatic blend of herbs and onions creates a symphony of flavors that’s both nostalgic and indulgent. Whether it’s a cozy dinner or a special occasion, this soup promises to delight your senses and satisfy your cravings. Perfect for sharing, it’s a dish that brings people together with every delicious bite.
Essential Ingredients for French Onion Soup
- 4 Tablespoons unsalted butter (plus extra for optional bread brushing)
- 3.5 lbs (1.6 kg) onions (a blend of sweet Vidalia and yellow onions recommended)
- 1 teaspoon granulated sugar
- ½ teaspoon salt
- 1 ½ Tablespoons all-purpose flour
- ⅔ cup (157 ml) dry white wine (Pinot Grigio used here)
- 8 cups (1.9 L) beef broth
- 3 sprigs fresh thyme (additional for optional topping)
- 2 dried or 1 fresh bay leaves
- ½ teaspoon freshly ground black pepper
- 8 oz Gruyere cheese, shredded (for topping)
- 1 loaf French bread, sliced into ¾” thick slices (for topping)
- 1 large garlic clove (for bread topping)
Step-by-Step Cooking Instructions
- Prepare the onions by slicing them root to stem, removing the outer layer, and then slicing with the grain in ⅛” slices. Set aside.
- Melt the butter in a large Dutch oven over medium heat. Add the sliced onions, sugar, and salt, stirring until all onions are coated with butter. Cover and cook for 10 minutes.
- Uncover and continue cooking, stirring as needed, until onions are caramelized, approximately 40-60 minutes. Stir frequently near the end to prevent burning, reducing heat if necessary. Deglaze with a small splash of beef broth if onions stick.
- Pour the wine over the caramelized onions and cook, stirring frequently, until the wine is absorbed and the alcohol smell is gone, about 3-5 minutes.
- Sprinkle flour over the onions, stirring and cooking on medium/low heat for 2 minutes.
- Add the beef broth (first half slowly, scraping the bottom of the pan), thyme, bay leaves, and black pepper. Stir well, increase heat to bring to a boil, then reduce heat and simmer for 15-30 minutes.
- Preheat your oven to 425F (220C) and arrange the oven rack to the upper third.
- Place bread slices on a baking sheet, optionally brushing each side lightly with melted butter. Toast in the oven for 5-10 minutes. Remove, rub one surface of each slice with half of the garlic clove.
- Taste the soup and add more salt as needed. Remove thyme sprigs and bay leaves.
- Assemble the soup by portioning into crocks, sprinkling a bit of Gruyere over the surface, topping with bread slices, and adding additional cheese. Arrange on a baking sheet and place in the oven’s top rack until the cheese is bubbly and golden brown.
- Serve the soup hot, optionally topped with additional fresh thyme.
Perfect Pairings: Serving Suggestions
French Onion Soup is a classic on its own, but it pairs beautifully with a crisp green salad or a charcuterie board for a more substantial meal. For a cozy dinner, serve it alongside a grilled cheese sandwich or a warm baguette with herbed butter. Don’t forget a glass of the same dry white wine you used in the soup to tie it all together!
Storing and Reheating Like a Pro
Store leftover soup in an airtight container in the fridge for up to 3 days. To reheat, warm it gently on the stovetop over medium heat, stirring occasionally. If the soup thickens, add a splash of beef broth to loosen it. For the cheesy topping, reheat individual portions in the oven at 350°F (175°C) until bubbly and golden.
Time-Saving Tips for Busy Cooks
To cut down on prep time, use a mandoline slicer for perfectly even onion slices. If caramelizing onions feels too time-consuming, cook them in a slow cooker on low for 8-10 hours—they’ll turn golden and sweet with minimal effort. For a quicker assembly, use pre-sliced baguette and pre-shredded Gruyere cheese.
Recipe Variations to Try
For a vegetarian twist, swap beef broth for a rich mushroom or vegetable broth. If you’re feeling adventurous, add a splash of brandy or sherry instead of white wine for a deeper flavor. You can also experiment with different cheeses like Emmental or Comté for a unique twist on the classic Gruyere topping.
Essential Equipment for Success
A large Dutch oven is key for evenly caramelizing the onions and simmering the soup. For the cheesy topping, oven-safe soup crocks are a must. If you don’t have them, use a baking dish and portion the soup into bowls after baking. A microplane grater is also handy for finely shredding the Gruyere cheese.
French Onion Soup
Ingredients
- 4 Tablespoons unsalted butter plus additional for brushing bread, optional
- 3.5 lbs onions I use a blend of sweet Vidalia and yellow onions.
- 1 teaspoon granulated sugar
- ½ teaspoon salt
- 1 ½ Tablespoons all-purpose flour
- ⅔ cup dry white wine I used Pinot Grigio
- 8 cups beef broth
- 3 sprigs fresh thyme plus additional for topping if desired
- 2 dried bay leaves or 1 fresh bay leaf
- ½ teaspoon freshly ground black pepper
For Topping
- 8 oz gruyere cheese shredded
- 1 loaf French bread sliced into ¾” thick slices
- 1 large garlic clove
Instructions
- Prepare onions by slicing root to stem, removing the outer layer, and then slicing with the grain in ⅛” slices (see post or video for detailed instructions and visual). Set aside.
- Melt butter in a large Dutch oven over medium heat.
- Add sliced onions, sugar, and salt and stir until all onions have been coated with butter. Cover and cook for 10 minutes.
- Uncover and continue to cook, stirring as needed, until onions are caramelized, this will take approximately 40-60 minutes. Near the end you will need to stir the onions frequently to keep them from burning and may need to reduce your heat. If the onions begin to stick to the bottom, simply deglaze the pan with a small splash of your beef broth.
- Once onions are caramelized, pour the wine over the onions and cook, stirring frequently, until the wine has been absorbed/cooked out and the alcohol smell is gone (about 3-5 minutes).
- Sprinkle flour over the onions and stir, cooking on medium/low heat for 2 minutes.
- Add beef broth (add the first half of this slowly, making sure to scrape the bottom of the pan as you do), thyme, bay leaves, and black pepper. Stir well and increase heat to bring to a boil.
- Once boiling, reduce heat and simmer for 15-30 minutes. Meanwhile, arrange your oven rack to the upper third of your oven and preheat oven to 425F (220C).
- Place your bread slices in an even layer on a baking sheet. If desired, brush each side lightly with melted butter. Once oven is preheated, cook the bread until lightly toasted, about 5-10 minutes. Remove from oven (don’t turn off the oven!) and slice the garlic clove in half. Rub the cut half of the garlic against one surface of each slice of bread (the bread will be hot! I usually hold the bread with tongs while I rub the garlic against the surface).
- Once soup has simmered, taste it and add more salt as needed (whether or not you need more and how much will vary greatly depending on the brand and type of broth you used). Remove thyme and bay leaves as you come across them.
- Assembly
- Portion soup into crocks and sprinkle a bit of Gruyere over the surface. Top with bread slices (as many as fit nicely into the crock) and then top with additional cheese.
- Arrange crocks on a baking sheet and place in the top rack of your oven and bake until cheese is bubbly and beginning to turn golden brown.
- Remove and serve, topped with additional fresh thyme if desired.