Classic French Onion Soup

Ingredients

• 5-6 large Sweet Onions (Vidalia or yellow onions, thinly sliced against the grain; aim for about 3.5 lb (1.5 kg))
• 5 tablespoons Unsalted Butter (Divided: 3 tbsp for caramelizing, 2 tbsp to finish soup)
• 1 tablespoon Extra Virgin Olive Oil (Divided: 1 tbsp for caramelizing onions)
• to taste Salt (Season onions at the start and adjust final soup seasoning)
• to taste Black Pepper (Freshly ground for final seasoning)
• 2 tablespoons Bourbon (Optional but adds depth; deglaze the pot)
• 295 ml Dry White Wine (Use a dry variety; reduces by ~70%)
• 1400 ml Beef Stock (Homemade or high‑quality store‑bought; lightly seasoned)
• 44 ml Dry Sherry (Adds a subtle nutty finish; cook off alcohol)
• 1 whole Baguette (Slice 1/2‑inch thick pieces; brush with olive oil before toasting)
• 85 g Gruyère Cheese (Grated; mixed with Gouda for topping)
• 85 g Gouda Cheese (Grated; mixed with Gruyère for topping)

Instructions

1. Slice the onions

   Trim the tops and bottoms off the sweet onions, halve them, peel, and slice thinly against the natural rings to create moon‑shaped slivers. Aim for about 3.5 lb (1.5 kg) total; add another onion if needed.

   Time: PT10M

2. Caramelize the onions

   In the heavy‑bottom pot, melt 3 Tbsp unsalted butter with 1 Tbsp olive oil over medium heat. Add the sliced onions, season with a pinch of salt, and stir to coat. Cook, stirring gently but frequently, for about 45 minutes, adjusting heat between medium and low as the onions darken. If they begin to stick, splash a tiny amount of water and continue folding rather than vigorous stirring.

   Time: PT45M

3. Deglaze with bourbon (optional)

   Add 2 Tbsp bourbon to the pot, increase heat, and let it boil until almost all liquid evaporates, about 2 minutes.

   Time: PT2M

4. Reduce white wine

   Pour in 295 ml dry white wine, bring to a rapid boil, and reduce by roughly 70% (about 3‑5 minutes).

   Time: PT4M

5. Add beef stock and simmer

   Stir in 1.4 L beef stock and a tightly tied bundle of thyme (or a few sprigs). Bring to a gentle simmer and cook for 20‑30 minutes, until the soup is slightly reduced and thickened.

   Time: PT25M

6. Finish the broth

   Stir in 44 ml dry sherry and let simmer 1‑2 minutes. Then whisk in the remaining 2 Tbsp unsalted butter until fully melted and emulsified. Season with salt and freshly ground black pepper to taste.

   Time: PT3M

7. Prepare cheese topping

   Grate 85 g Gruyère and 85 g Gouda, then combine in a small bowl.

   Time: PT5M

8. Toast baguette slices

   Brush 1/2‑inch thick baguette slices with a little olive oil, place on a baking sheet, and bake at 425°F (218°C) until crisp but not browned, about 5‑7 minutes.

   Time: PT7M

   Temperature: 425°F

9. Assemble and broil

   Ladle hot soup into oven‑safe bowls, leaving a quarter‑inch headspace. Top each with 1‑2 toasted baguette slices, then sprinkle generously with the cheese mixture. Place bowls under a preheated broiler for 2‑3 minutes, until the cheese is melted, bubbly, and lightly browned.

   Time: PT3M

   Temperature: Broiler

10. Serve

    Allow the soup to sit for a minute, then serve hot with extra cheese or toasted bread on the side if desired.

    Time: PT0M

Nutrition Facts

Calories

420

Protein

12 g

Carbohydrates

45 g

Fat

18 g

Fiber

4 g

Ingredient Substitutions

• Instead of Sweet Onions: Yellow onions
• Instead of Unsalted Butter: Salted butter (reduce added salt), Margarine
• Instead of Extra Virgin Olive Oil: Canola oil, Vegetable oil
• Instead of Bourbon: Dry sherry, Brandy
• Instead of Dry White Wine: Additional beef stock
• Instead of Beef Stock: Chicken stock (different flavor)
• Instead of Dry Sherry: Marsala wine, Additional sherry
• Instead of Baguette: Sourdough loaf, Italian bread
• Instead of Gruyère Cheese: Swiss cheese
• Instead of Gouda Cheese: Mild cheddar

Equipment Needed

• 6‑8 quart heavy‑bottom pot
• Chef's knife
• Cutting board
• Wooden spoon or heat‑proof spatula
• Ladle
• Oven‑safe bowls or ramekins
• Baking sheet
• Broiler (oven setting)
• Measuring cups and spoons
• Kitchen scale (optional)
• Tongs (optional)

Critical Steps — Do Not Skip

• Caramelize onions until deep golden brown (about 45 minutes).
• Deglaze the pot with bourbon and reduce.
• Reduce white wine by roughly 70%.
• Simmer beef stock with thyme until slightly thickened.
• Finish the broth with sherry and butter for a glossy texture.
• Toast baguette slices until crisp.
• Broil cheese‑topped soup until melted and lightly browned.

Chef Tips from the Video

• Use sweet Vidalia onions for natural caramel sweetness; a pinch of sugar can help if onions are less sweet.
• A heavy‑bottom pot prevents scorching during the long caramelization.
• Deglazing with bourbon adds depth; if you skip it, increase sherry by 1 Tbsp.
• Finish with butter off the heat for a silkier mouthfeel.

Troubleshooting

Storage

Refrigerator: Store soup in an airtight container for 3‑4 days. Reheat gently on the stove.

Freezer: Freeze in freezer‑safe containers for up to 2 months. Thaw overnight and reheat.

Room temperature: Do not store at room temperature for more than 2 hours.

Make-Ahead Tips

• Caramelize the onions a day ahead and store them in the fridge; reheat before adding stock.
• Prepare homemade beef stock in advance or use high‑quality store‑bought stock.
• Grate the cheeses and keep them sealed; they melt faster when at room temperature.
• Toast baguette slices just before serving for maximum crispness.

Frequently Asked Questions