Savory French Onion Soup with Caramelized Onions and Gruyère

By AislePrompt Editorial · Published 2026-05-01 · Updated 2026-05-01

Traditional French onion soup featuring deeply caramelized onions simmered in beef broth, topped with toasted baguette and melted Gruyère cheese. This French-inspired soup recipe (vegetarian option with broth swap), ready in about 90 minutes, pairs yellow onions, unsalted butter, olive oil for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 350 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 large, thinly sliced yellow onions
• 3 tbsp unsalted butter
• 1 tbsp olive oil
• 1 tsp sugar
• 1/2 cup dry white wine
• 6 cups beef broth
• 3 fresh thyme sprigs
• 1 bay leaf
• 1 tsp salt
• 1/2 tsp black pepper
• 8 slices, about 1/2 inch thick baguette slices
• 2 cups shredded Gruyère cheese

The stock pot we’d simmer this in → Best Stock Pots for 2026: Top Picks + Buying Guide

Instructions

1. Step 1: In a large heavy-bottomed pot, melt 3 tbsp unsalted butter and 1 tbsp olive oil over medium heat. Add 4 large thinly sliced yellow onions and 1 tsp sugar. Cook slowly, stirring frequently, for 40 minutes until onions are deeply caramelized and golden brown.
2. Step 2: Pour in 1/2 cup dry white wine and cook for 5 minutes, scraping up any browned bits from the pot bottom.
3. Step 3: Add 6 cups beef broth, 3 fresh thyme sprigs, 1 bay leaf, 1 tsp salt, and 1/2 tsp black pepper. Bring to a simmer and cook gently for 30 minutes to meld flavors.
4. Step 4: Meanwhile, preheat broiler. Arrange 8 slices of baguette on a baking sheet and toast under broiler for 2 minutes per side until golden and crisp.
5. Step 5: Remove thyme sprigs and bay leaf from the soup. Ladle soup into oven-safe bowls, place toasted baguette slices on top, and sprinkle evenly with 2 cups shredded Gruyère cheese.
6. Step 6: Place bowls under broiler for 3-4 minutes until cheese is melted, bubbly, and lightly browned. Serve immediately.