Classic French Onion Soup
When the weather takes a turn, Classic French Onion Soup topped with cheesy croutons is comfort food that will hit the spot!
I tweaked my tried and true recipe by using two types of broth and adding some herbs. This was the Best French Onion Soup Recipe to come out of my kitchen! I bet you’ll love it as much as we did.

Why You Must Make
I adore baking, but I still have to get dinners ready for a family of 5, which is not nearly as much fun. When somebody actually requests a dish, I’m delighted to comply! My oldest recently asked if I could make French onion soup. So within days, it was on our menu.
- If you’ve never caramelized onions, this recipe will prove their deliciousness.
- The Gruyere-topped croutons are irresistible.
- This is comfort food on a chilly day!
I slowly caramelized some thinly sliced Spanish onions along with a bit of minced garlic. A tablespoon of flour was sprinkled over them once they reached a golden brown color, and then dry white wine and broth were added. Bill and I picked up our youngest, Nick, from a 4-day retreat with his high school classmates, and the closing ceremony lasted well past our dinnertime. When we all arrived home, with one who was sleep-deprived and desperately needed a shower, we quickly rewarmed this aromatic soup, added a slosh of cognac, and broiled each bowl with a Gruyere-topped crouton.
My broiler was on the fritz (yes, my oven saga continues), so I didn’t get the golden crust I was hoping for, but any melted cheese was better than none! It truly hit the spot on a cool autumnal evening.

Recipe Tips
French onion soup has always been a favorite. It’s all about the bread and gooey cheese topper. My favorite version to date is this combination of Dorie Greenspan’s and Thomas Keller’s recipes with a few tweaks of my own.
- Taking time to fully caramelize the onions will magnify the delectable flavors. This is a slow process that takes patience but is worth the effort. Start with a sweeter onion, like the yellow onions I selected. They should slowly brown but not burn, and must be stirred frequently. Caramelized onions give an amazing depth of deliciousness.
- PRO-Tip: You can also caramelize onions in your slow cooker (Food Network link). All you’ll need is sliced onions and some canola oil. I might go with butter instead. So easy!
- I added a bay leaf and a bit of fresh thyme to this French onion soup for another dimension. Layering flavors is key.
- My best French onion soup is made with both Beef Broth and Chicken Broth from a box, but I’m certain it would be even more incredible with homemade stock. I prefer store-bought chicken broth to beef, but the combination is really nice. I prefer the Pacific brand as it’s less salty than Swanson’s. I’ve even seen it at Target.
- Watch the sodium if you’re using some of those canned/boxed brands of broth or stock. Some are so salty that they can ruin your soup.
- PRO-Tip: Did you know alcohol is a flavor enhancer? The deglazing of the pan with white wine and the addition of cognac both help make this an incredibly delicious soup. Note, the alcohol evaporates while cooking, leaving just flavor. This makes it OK to serve to children.
- PRO-Tip: Alton Brown added a teaspoon of Fish Sauce for the ultimate umami boost. It’s going in my next batch!
- My favorite part of this dish is the cheesy crouton served on top of the soup! I toasted both sides of a long diagonal slice of a baguette in the oven, then placed one or two on the bowl of soup, and finally topped it with a generous amount of shredded Swiss cheese.
- Next, the soup bowls were popped under the broiler until hot, gooey, and golden! Gruyere is a classic cheese choice, but I love mixing half and half Gruyere and Emmenthal. More depth of flavor again!
- My friend, Marissa, of Pinch and Swirl, cut her bread into croutons, so I followed suit with a few bowls. It was definitely easier to eat! She used Julia Child’s recipe if you want to peek at that, too.

Frequently Asked Questions
Yes, it became popular in the 1800s in Les Halles, a Parisian open market. Restaurants in the area served their onion soup with a cheese topping that they placed under a grill to melt.
Yellow onions are preferred since they are sweeter than white onions and caramelize beautifully. Red onions will alter the color of what’s considered classic for a French onion soup.
Make sure to season well with salt and pepper to suit your palate. Add herbs that complement your soup. Use flavor enhancers like alcohol, which if added early will evaporate, while bolstering the flavor. There are other sources of umami, or the savory sense of taste, like Worcestershire sauce, soy sauce, fish sauce, and even a Parmesan rind that provide nice flavor if they’re appropriate for your soup recipe.
Deglazing is a process done after meat or other ingredients have been sauteed in oil or fat. A bit of liquid (broth, stock or wine) is added to help loosen the tasty browned bits left in the pan. This flavorful mixture can be used to make a sauce or gravy.
You May Also Like
If you’re making a batch of caramelized onions for this onion soup, then why not toss in an extra onion and use the extras to enhance some other recipes!
- Fig, Goat Cheese and Prosciutto Pizzas
- French Onion Marmalade is a fabulous burger topping and is made similarly with brown sugar and vinegar.
- Bacon Burgers with Caramelized Onions from Recipe Girl
- White Barbecue Pizza with Prosciutto and Caramelized Onions from A Family Feast
Classic French Onion Soup
A rich onion laden broth flavored with herbs, white wine and cognac and topped with cheesy toast!
Ingredients
- 4 pounds yellow onions
- 2 tablespoons butter
- 2 tablespoons olive oil
- 3-4 cloves of garlic, minced
- Kosher salt
- 1 tablespoon flour
- 1 cup dry white wine (or vermouth)
- 2 cups beef broth
- 2 cups chicken broth
- 2 bay leaves
- 2 sprigs of fresh thyme
- Freshly grated black pepper to taste
- ¼ cup Cognac
- 1 ½ cups grated Swiss cheese (I used half Gruyere and half Emmental)
- Baguette, cut into ½ inch slices
- Olive oil and kosher salt to toast baguette
Instructions
- Peel onions, then cut in half through the root. Cut each half into thin slices. In a Dutch oven, heat olive oil and butter.
- Add onions, and garlic and sprinkle with Kosher salt. Slowly cook, over low heat, stirring frequently until
- the onions start to caramelize. Do not allow them to burn, but continue cooking till the onions are browned.
- When the onions are caramelized, add flour and cook for a minute or two to cook off the raw flour taste. Add wine or vermouth and reduce the liquid by about half.
- Add both types of broth, and bring to a boil. Reduce heat and allow soup to simmer for at least 30 minutes. Add cognac and stir. Check for seasoning, adding black pepper and more salt to taste if needed.
- Prepare croutons by brushing with olive oil and a sprinkle of Kosher salt. Broil till lightly toasted. Flip, brush with olive oil, and broil backside. Set aside. Watch carefully as these can burn quickly.
- Fill heat-proof bowls with soup, leaving room to top with crouton. Place crouton over soup and put about ¼ cup grated cheese over the toasts. Or like my friend, Marissa from Pinch and Swirl, make smaller croutons out of your slice and top those with cheese.
- Place bowls on a sheet pan and place under the broiler. Broil till cheese is melted, bubbly, and lightly brown. Serve immediately.
Notes
Deglazing the pan is key to building flavor. The alcohol will burn off, so it isn't a worry when serving it to children.
Adapted from recipes by Thomas Keller and Dorie Greenspan.
Nutrition Information:
Yield:
6Serving Size:
1Amount Per Serving: Calories: 598Total Fat: 21gSaturated Fat: 9gTrans Fat: 0gUnsaturated Fat: 10gCholesterol: 37mgSodium: 1300mgCarbohydrates: 74gFiber: 7gSugar: 19gProtein: 21g

35 Comments on “Classic French Onion Soup”
I adore French Onion Soup – one of my all time favorites! I love how you’ve tweaked this recipe over many years to perfect it – definitely must try! Have a lovely weekend, my friend!
It’s been a long time since I have visited your blog and oh what a treat! French Onion soup when done right is absolutely comfort soup. Looks like you aced both the recipe and the final product Liz! Well done!
We LOVE french onion soup here. Love the addition of the cognac!
This is delicious! So much flavor and richness in one bowl!
Looks amazing! I love French onion soup! I have to try your recipe Lizzy!
Oh Liz, I love French onion soup but never made it myself…thank you so much for the recipe as the soup season is here.
I hope you are having a wonderful week!
We’ve had ~a few~ rainy days… This would be perfect for lunch:@)
Sensational! I love the soup season and this French onion soup is definitely a winner, Liz.
Definitely love to try! xoxo
So glad you visited, Giorgia!
Great, Leslie!!! I started making this by following a Dorie Greenspan recipe which called for chicken broth. But I do think that canned chicken broth is superior to beef broth…so since I wasn’t making it from scratch, it seemed a change for the better. Thanks for stopping by!
Leef, it was really, really good! Tom and Bill each toasted their own bread and broiled the cheese topping 3 days in a row! Now, that’s an endorsement 🙂
What was your opinion of this dish? It looks good. I love the frozen individual ones I could get at Costco, but last time I was there they didn’t have them. Do you think it might have something to do with it being 110 outside?? Hope it returns this fall. I’ve never attempted to make it from scratch, but I’ll have to if they no longer carry it.
You’re so sweet, Paulette!!! Thanks!
Thanks, everyone…it was 96º today and I still managed to eat a bowl! I’ll definitely make another batch when there’s an arctic chill in the air~
Liz, Frank and I love onion soup and this one looks so yummy. I look forward to all your recipes and photos.
Looks delicious Liz!
We adore onion soup…
As soon as it cools off a bit I will be making some!
I stubbornly am resisting autumn (and luckily, our temps will be back in the 90s again) because I hate to see Summer go; however, I’ll be making this when the temps are much cooler here.
Photos look terrific, Liz.
Lizzy, Your French onion soup is beautiful! Love the crouton and all that yummy melted cheese. Not to mention the spike flavor from the vermouth, and cognac! Wow! I’m so impressed! Thanks for sharing!
Lizzie
Yay for soups! Liz, this looks like a lovely recipe. I definitely will be making this soon!
Yummy, yummy…….I guess Lambeau isn’t into soups. 🙂
Thanks for sharing another great recipe Lizzy.