Soupe à l'Oignon Gratinée
Indulge in this quintessential French Onion Soup, featuring deeply caramelized onions simmered in a rich, savory beef broth. Each spoonful offers a harmonious blend of sweet, umami, and herbaceous notes, crowned with a golden, bubbly layer of melted Gruyère cheese over toasted baguette. It's a comforting and elegant dish, perfect for a cozy evening.
An original recipe by Forkin
- Total time
- 1 hr 50 min
- Serves
- 4
- Difficulty
- Medium
- Per serving
- 524 kcal
Allergen information: may contain gluten, milk, and sulphites. Always check ingredient packaging if you have an allergy.
Mise en place
Ingredients
Converted for display; the recipe amounts stay equivalent.
- 1,000 gyellow onion, thinly sliced
- 60 gunsalted butter
- 15 mlolive oil
- 2 clovegarlic, minced
- 15 gall-purpose flour
- 120 mldry white wine
- 1,000 mlbeef broth
- 3 pcsfresh thyme sprig
- 1 pcsbay leaf
- 1 tspsalt
- 0.5 tspblack pepper, freshly ground
- 8 slicebaguette, cut into 1-inch (2.5 cm) thick slices
- 150 ggruyère cheese, grated
Equipment
Large heavy-bottomed pot or Dutch oven · Chef's knife · Cutting board · Wooden spoon · 4× Oven-safe bowls · Baking sheet · Grater · Ladle
The method
Step by step
- 1
Thinly slice the yellow onions using a sharp knife or mandoline.
About 10 min
Cook’s note: Uniformly sliced onions ensure even caramelization, which is key to the soup's flavor.
- 2
Melt the unsalted butter with the olive oil in a large, heavy-bottomed pot or Dutch oven over medium-low heat.
About 2 min
Cook’s note: Using a heavy-bottomed pot helps distribute heat evenly and prevents scorching during the long caramelization process.
- 3
Add the sliced yellow onions and a generous pinch of salt to the pot. Cook, stirring occasionally, for 40-50 minutes until the onions are deeply golden brown, soft, and intensely sweet.
About 50 min
Cook’s note: Patience is paramount here; true caramelization develops slowly and is the foundation of the soup's rich flavor. Don't rush this step.
- 4
Mince the garlic cloves.
About 2 min
- 5
Stir the minced garlic into the caramelized onions and cook for 1 minute until fragrant.
About 1 min
Cook’s note: Be careful not to burn the garlic, as it can turn bitter quickly.
- 6
Sprinkle the all-purpose flour over the onion mixture and stir continuously for 2 minutes, allowing it to cook and lightly toast.
About 2 min
Cook’s note: This step creates a roux that will slightly thicken the soup and prevent the broth from separating.
- 7
Pour in the dry white wine, scraping the bottom of the pot with a wooden spoon to deglaze and release any flavorful browned bits.
About 3 min
Cook’s note: Choose a dry white wine like Sauvignon Blanc or Pinot Grigio; avoid sweet wines.
- 8
Add the beef broth, fresh thyme sprigs, and bay leaf to the pot. Bring the soup to a gentle simmer.
About 5 min
Cook’s note: Use a good quality beef broth for the best flavor; homemade is ideal if available.
- 9
Reduce the heat to low, cover the pot, and simmer for 20 minutes to allow the flavors to fully meld and deepen.
About 20 min
Cook’s note: A slow simmer ensures the herbs infuse their flavor into the broth without becoming overpowering.
- 10
While the soup simmers, preheat your oven broiler to high.
- 11
Arrange the baguette slices in a single layer on a baking sheet. Toast them under the preheated broiler for 1-2 minutes per side, until golden brown and crisp.
About 4 min
Cook’s note: Keep a close eye on the baguette slices as they can burn very quickly under the broiler.
- 12
Carefully remove the thyme sprigs and bay leaf from the soup. Season the soup with salt and black pepper to taste.
About 1 min
Cook’s note: Taste and adjust seasoning as needed; the saltiness of the broth can vary.
- 13
Ladle the hot soup into individual oven-safe bowls.
About 2 min
Cook’s note: Ensure the bowls are truly oven-safe to prevent cracking under high heat.
- 14
Float two toasted baguette slices on top of the soup in each bowl.
- 15
Generously sprinkle the grated Gruyère cheese over the baguette slices, ensuring full coverage.
About 1 min
Cook’s note: Gruyère is traditional, but Comté or Emmental can be used as alternatives for their excellent melting properties.
- 16
Place the bowls on a baking sheet and broil for 2-4 minutes, or until the cheese is melted, bubbly, and beautifully golden brown.
About 4 min
Cook’s note: Watch the cheese constantly to prevent burning; the transition from golden to burnt can happen in seconds.
- 17
Serve immediately and with caution, as the bowls will be extremely hot.
Cook’s note: Place the hot bowls on heat-resistant mats or trivets for serving.
Per serving
Nutrition
- Calories
- 524.1kcal
- Protein
- 20.3g
- Carbs
- 41.8g
- Fat
- 29.1g
- Fibre
- 5.4g
- Sugar
- 12.1g
Estimated from the recipe’s ingredient quantities. Values can vary with brands and substitutions.
Keep it good
This classic French Onion Soup pairs wonderfully with a crisp green salad and a glass of dry white wine, such as Sauvignon Blanc or Pinot Grigio. For a heartier meal, serve it alongside a simple roast chicken or a crusty bread. A vegetarian version can be made by substituting vegetable broth for beef broth, though the flavor profile will be different.
Store leftover soup (without the bread and cheese topping) in an airtight container in the refrigerator. Store toasted baguette separately in an airtight container at room temperature.
Reheat the soup gently on the stovetop over medium-low heat until simmering. Prepare fresh baguette and cheese topping just before serving.
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