Ingredients
Scale
- 6 large yellow onions, thinly sliced
- 4 tablespoons unsalted butter
- 1 tablespoon olive oil
- 1 teaspoon salt
- 1 teaspoon sugar (helps caramelize)
- 2 cloves garlic, minced
- 1/2 cup dry white wine (or sherry)
- 8 cups beef stock (homemade or high-quality store-bought)
- 1 bay leaf
- 4 sprigs fresh thyme (or 1 teaspoon dried)
- Salt and black pepper, to taste
For the Topping:
- 1 baguette, sliced into 1-inch thick rounds
- 2 cups grated Gruyère cheese (or Swiss/Emmental as backup)
- Optional: splash of brandy or cognac
Instructions
- Slice and Sweat the Onions: Melt butter and olive oil in a heavy-bottomed pot over medium heat. Add onions, salt, and sugar. Cook, stirring frequently, for 40–50 minutes until deeply golden and caramelized.
- Add Garlic and Deglaze: Stir in garlic, cook for 1 minute. Add wine to deglaze the pan, scraping up all those delicious brown bits.
- Simmer the Broth: Add beef stock, bay leaf, thyme, and optional splash of brandy. Bring to a simmer. Cover loosely and cook for 30–40 minutes.
- Toast the Bread: While the soup simmers, toast baguette slices under the broiler until golden. Set aside.
- Season to Taste: Remove herbs from the soup. Season with salt and pepper as needed.
- Assemble the Bowls: Ladle soup into oven-safe bowls. Top with a baguette slice and a handful of grated cheese.
- Broil Until Bubbling: Place bowls on a baking sheet and broil 2–3 minutes, or until cheese is bubbly and browned.
- Serve Hot: Let sit for a minute (molten cheese is no joke), then serve.
Notes
- Don’t rush the onions: They’re the backbone—deep flavor only comes with time.
- Try vegetable stock for a vegetarian version: Still rich, still delicious.
- Mix up the cheese: Comté, provolone, or a sharp cheddar bring unique notes.
- No oven-safe bowls? Toast bread with cheese separately, then float it on top.
- Make it ahead: Soup gets better with time. Reheat gently and broil before serving.