Description
Experience the comforting warmth of a true French classic with this authentic soupe à l’oignon gratinée. In this recipe, golden onions are patiently caramelized in butter and olive oil to release their deep sweetness—no sugar shortcut required. A splash of dry white wine lifts their flavor before rich beef broth, aromatic thyme, and bay leaf create a base that simmers until irresistibly fragrant. Just before serving, thick slices of toasted baguette are layered over the soup and buried under a generous crown of melted, bubbling gruyère cheese, forming a perfect gratin crust. Serve piping hot in individual bowls on a chilly evening and let each spoonful of savory, cheesy, onion-laden comfort become a new family tradition.
Ingredients
- 800 g d’oignons jaunes
- 40 g beurre doux
- 1 cuillère à soupe huile d’olive
- 1 grosse gousse d’ail, hachée
- 15 cl vin blanc sec
- 1 l bouillon de bœuf
- 2 feuilles de laurier
- 4 branches thym frais
- 1 baguette de pain rassis (environ 200 g), en tranches de 2 cm
- 150 g gruyère râpé
- 1 cuillère à café sel fin
- 1/2 cuillère à café poivre noir moulu
Instructions
- In a large pot over medium-low heat, melt the butter with the olive oil. Add the sliced onions and half the salt. Stir to coat, cover, and let them sweat for 10 minutes until softened.
- Remove the lid, reduce the heat if needed, and cook the onions, stirring and scraping the bottom regularly, for 35–40 minutes. Continue until onions are deeply golden brown, shiny, and reduced by a third. Don’t increase the heat—patience is key.
- Pour in the dry white wine, and turn the heat up to medium-high. Scrape the bottom of the pot to deglaze, dissolving all browned bits. Let simmer for 2–3 minutes until most of the alcohol smell disappears.
- Stir in the chopped garlic, hot beef broth, bay leaves, thyme, remaining salt, and black pepper. Bring just to a simmer, then lower the heat and cook gently, uncovered, for 40–50 minutes. Taste and adjust seasoning if needed. Remove the thyme and bay leaves.
- While the soup simmers, preheat your oven to 220°C. Arrange the baguette slices on a baking tray and bake for 7 minutes, turning halfway, until dry and crispy on both sides. Let cool.
- Ladle the hot soup into 4 ovenproof bowls, filling each to about 2 cm from the rim.
- Place 2–3 toasted baguette slices on top of each bowl of soup, pressing lightly so they absorb a little of the broth. Evenly distribute the grated gruyère over the bread for each bowl.
- Place the bowls on a baking sheet and transfer to the oven under the grill (broiler) set to 220°C. Broil 10–15 minutes, watching carefully, until the cheese bubbles and turns golden brown. Remove and let rest 5 minutes before serving.
- Prep Time: 20 minutes
- Cook Time: 1 hour 50 minutes
- Category: Soup
- Method: Baking
- Cuisine: French
Nutrition
- Serving Size: 1 serving
- Calories: 533
- Sugar: 9.2 g
- Sodium: 1537 mg
- Fat: 19.7 g
- Saturated Fat: 11.15 g
- Unsaturated Fat: 8.2 g
- Trans Fat: 0.52 g
- Carbohydrates: 62.4 g
- Fiber: 4.6 g
- Protein: 21.6 g
- Cholesterol: 46 mg
Keywords: Use only yellow onions for that perfect balance of sweetness and savoriness—red onions tend to make the soup too sweet and colorful. Gruyère or comté both offer an authentic taste and ideal melting texture; avoid emmental if possible, as it’s bland and too stringy. Use stale (day-old) bread for the best gratin; fresh bread will dissolve. Country bread can be substituted for baguette. For a vegetarian version, substitute beef broth with vegetable broth and ensure your cheese is vegetarian-friendly. If preparing ahead, only assemble with bread and cheese just before serving so the gratin crust is crisp and the bread doesn’t become soggy.