Baked French Onion Soup with Gruyère and Thyme

By AislePrompt Editorial · Published 2026-04-09 · Updated 2026-04-09

A classic French onion soup with caramelized onions and a golden, bubbling layer of Gruyère cheese, finished with a hint of fresh thyme. This French-inspired soup recipe, ready in about 60 minutes, pairs onion, butter, all-purpose flour for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 380 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 4 medium, thinly sliced onion
• 2 tbsp butter
• 1 tbsp all-purpose flour
• 4 cups beef broth
• 1/2 cup dry white wine
• 1 tsp dried thyme
• 1/2 cup, grated Gruyère cheese
• 1 slice, cut into 1/2-inch thick slices baguette
• to taste salt
• to taste black pepper

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Instructions

1. Step 1: Preheat the oven to 375°F (190°C).
2. Step 2: In a large pot over medium heat, melt 2 tbsp butter; add 2 cups thinly sliced onions and cook, stirring occasionally, until deeply caramelized and golden brown, about 25-30 minutes.
3. Step 3: Stir in 1 tbsp all-purpose flour and cook for 1 minute, then add 4 cups beef broth, 1/2 cup dry white wine, and 1 tsp dried thyme; bring to a simmer and cook for 10 minutes.
4. Step 4: Season with salt and pepper to taste.
5. Step 5: Pour the soup into 4 oven-safe bowls, then place 1 slice of baguette in each bowl.
6. Step 6: Sprinkle 1/4 cup grated Gruyère cheese over each bowl, then place the bowls on a baking sheet and bake until the cheese is melted and golden, about 10-12 minutes.