Easy French Onion Soup (With Cheesy Gruyere Toast)
French onion soup is one of those dishes that feels fancy but is really just a few simple ingredients. Sweet, golden onions simmer in a rich beef broth. Then each bowl gets a crisp toast and a thick layer of melted Gruyere.
The only secret is patience. Slowly caramelizing the onions builds all the deep, sweet flavor. Once that’s done, the rest comes together fast.
I love making this in my kitchen on a slow winter weekend. It’s also a lovely starter for a cozy holiday dinner.
Why You’ll Love This French Onion Soup
- Restaurant quality. Tastes like your favorite bistro bowl.
- Simple ingredients. Onions, broth, butter, bread and cheese.
- Cheesy topping. Bubbly, golden Gruyere on every bowl.
- Make-ahead friendly. The soup gets better after a day.
- Budget friendly. Onions are cheap, but the flavor is rich.
Ingredients You’ll Need
The exact amounts are in the recipe card at the end of this post.
- Yellow onions: They have the best balance of sweet and savory. Sweet onions work too.
- Beef broth: Use a good-quality, low-sodium broth. A mix of beef and chicken broth is also nice.
- Wine: Dry white wine or dry sherry adds brightness. Use more broth if you prefer.
- Bread: A sturdy baguette, toasted until dry, holds up best.
- Gruyere: Classic and nutty. Swiss or provolone are good swaps.
How to Make French Onion Soup
- Caramelize. Cook the onions in butter and oil with salt for 45 to 60 minutes until deep golden.
- Deglaze. Add the garlic, then the wine. Scrape up the brown bits.
- Simmer. Add the broth, Worcestershire and herbs. Simmer 25 to 30 minutes.
- Toast. Bake the baguette slices at 400°F (200°C) until crisp.
- Broil. Ladle into oven-safe bowls, add toast and cheese, and broil 2 to 4 minutes until bubbly.
My Tips for the Best French Onion Soup
- Don’t rush the onions. High heat burns them before they turn sweet.
- Add a splash of water whenever the bottom of the pot gets too dark.
- Slice the onions evenly so they cook at the same rate.
- Toast the bread well so it doesn’t turn soggy in the soup.
- Watch the broiler closely and use oven mitts. The bowls get very hot.
Variations to Try
- Brandy: Add 2 tbsp brandy with the wine for extra depth.
- Mixed onions: Use a mix of yellow, sweet and red onions.
- No broiler bowls: Melt the cheese on the toasts on a baking sheet and float them on top.
- Slow cooker: Caramelize the onions in the slow cooker on LOW for 10 hours, then add broth.
Make-Ahead, Storage and Reheating
- Make ahead: Make the soup up to 3 days ahead without the bread and cheese.
- Storage: Refrigerate up to 4 days or freeze up to 3 months. Keep toasts in an airtight bag.
- Reheating: Bring the soup to a simmer, then top with toast and cheese and broil.
What to Serve With It
French onion soup pairs beautifully with a crisp, bright salad. Try it with my Christmas Salad With Pomegranate and Feta for a cozy but balanced holiday meal.
Frequently Asked Questions
How long does it take to caramelize onions? About 45 to 60 minutes over medium to medium-low heat. Don’t rush it.
What cheese is best for French onion soup? Gruyere is the classic. Swiss, provolone or a mix with Parmesan also work.
Can I make it without wine? Yes. Use more broth and a teaspoon of balsamic or sherry vinegar for brightness.
I don’t have oven-safe bowls. What can I do? Broil the cheese on the toasts on a baking sheet, then place them on top of each bowl.
One Last Thing
I hope this easy French onion soup becomes a winter favorite at your house. If you make it, please leave a comment and a star rating below. And save it to your soup board on Pinterest!
French Onion Soup
Ingredients
Soup:
- 4 tbsp unsalted butter
- 1 tbsp olive oil
- 3 lb yellow onions about 5 large, halved and thinly sliced
- 1 tsp salt plus more to taste
- 1/2 tsp sugar optional, helps browning
- 3 cloves garlic minced
- 1/2 cup dry white wine or dry sherry or more broth
- 8 cups low-sodium beef broth
- 1 tbsp Worcestershire sauce
- 1 tsp dried thyme or 4 fresh sprigs
- 1 bay leaf
- 1/2 tsp black pepper
Topping:
- 6 slices baguette 1 inch thick
- 8 oz Gruyere cheese shredded (about 2 cups)
- 1/4 cup Parmesan cheese grated, optional
Instructions
- Melt the butter with the olive oil in a large Dutch oven over medium heat. Add the onions and salt and stir to coat.
- Cook, stirring every few minutes, for 45 to 60 minutes, until the onions are deep golden brown and jammy. Add the sugar after 15 minutes. Lower the heat if the bottom starts to burn and add a splash of water to loosen the brown bits.
- Add the garlic and cook 1 minute. Pour in the wine and scrape the bottom of the pot. Simmer until almost gone, about 2 minutes.
- Add the broth, Worcestershire, thyme, bay leaf and pepper. Simmer uncovered for 25 to 30 minutes. Remove the bay leaf and taste for salt.
- Meanwhile, toast the baguette slices at 400°F (200°C) for 6 to 8 minutes until dry and crisp.
- Set the oven to broil. Ladle the soup into oven-safe bowls on a baking sheet. Top each with a toast and a big handful of Gruyere (and Parmesan). Broil 2 to 4 minutes until bubbly and browned. Watch closely. Bowls will be very hot.
Notes
Storage: Refrigerate the soup up to 4 days or freeze up to 3 months. Store toasts separately in an airtight bag.
Reheat: Warm the soup on the stove until simmering, then add toast and cheese and broil.
Variations: Use a mix of beef and chicken broth, swap Gruyere for Swiss or provolone, or add a splash of brandy with the wine.
