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Published December 31, 2018. This post may contain affiliate links. Please read my disclosure policy.
Make this Classic French Onion Soup Recipe with Crostini and Gruyere Cheese that is topped off with fresh thyme and perfect on cold days!
There is not much out there that makes me happier than a delicious warm pot of soup, and more specifically a classic French onion soup recipe. If you make it you appreciate the robust flavors, even more, knowing you spent at least 15 minutes crying over peeling and slicing onions and then again when caramelizing them over an hour while constantly stirring.
Onions in their raw form are great on a burger, in ceviche, or possibly with tartar, but onions that are caramelized belong on just about anything, including a soup.
How to Cut an Onion Without Crying
The first time I made a classic French Onion Soup recipe I was probably only about 15 years old. I was working at a country club down in good ole’ Eureka, Missouri and was tasked with making a classic French onion soup recipe for a special over a cold winter weekend.
I remember being in the prep station and literally crying as I was cutting onions. Groundsmen and maintenance folks were strolling through and laughed as they noticed the tears rolling down my face as if I had sliced a finger off or perhaps got dumped by a girlfriend.
Once they realized the reason for the tears they all offered advice and one guy even tried to give me his safety goggles as if that would do anything while trying to make this recipe.
I’ve heard all the tricks to stop crying when it comes to slicing onions and honestly I’m not sure if any of them work because I’ve tried them all. The only thing I found that really works is totally focusing on breathing only out of our mouth without one small gasp coming in through your nose. Now I’m not saying it will work for you, but it may make your onion soup recipe making a little more enjoyable.
For my classic recipe, I used a simple combo of yellow and white onions but you can absolutely use just yellow, just white or even add in some red onions or leeks, honestly, it’s up to you. We used to make a 5 onion soup at a different restaurant I worked at where we used white, yellow, red, leeks and garlic and then topped off with a bleu cheese crouton.
Talk about an intense combination of flavors?! That restaurant really allowed me to cut my culinary chops and opened up my taste buds to a whole new world of flavors.
How to Caramelize the Onions
Once your onions are cut cook them in butter over medium-low heat until they are tender and browned. This is the longest part of the recipe as it takes about 60 minutes. It takes time to caramelize that many onions and you definitely do not want to rush this part because this is where all the flavor of the soup comes from.
Occasionally I add a little bit of sugar to help sweeten up the onions as well as help to caramelize. Sugar makes caramel so it’s kind of the same thing in this soup. Sometimes you may find that your onions aren’t getting sweet maybe because of the way that specific batch is and you may need some sugar.
I recommend tasting your onions first to see if they need more sweetness. You want to make sure they are sweet enough so that your soup recipe is perfect!
How to Make French Onion Soup
Once they are browned deglaze with a dry red wine to help counter the balance of the sweet caramelized onions. At this point, you want to cook it until most of the liquid has been absorbed into the onions, which takes about 10 minutes or so. I know it seems like it’s been forever but you’re one step closer to making this.
Add in the beef stock and let the soup simmer for as long as you can take it without dying to eat it. Soup always tastes better the longer it cooks because it gives it time for all of the flavors to come out. Going back to the beef stock thing, you can do ½ beef and ½ chicken, totally up to you but I definitely don’t recommend doing all chicken as your soup will be way too light in color.
The last thing you really want to do with this soup is to finish it with fresh chopped thyme and salt and pepper.
Before you eat the soup add on a few crostini’s or croutons and then load it up with as much shredded gruyere that’ll fit over top and then broil it for a few minutes. Gruyere is a must there by the way as it’s the traditionalist way and it also just makes the flavor of the onion soup insane so do it. Before I’m out, try serving them with some French Gougéres.
More Amazing Soup Recipes
- Texas-Style Chili Recipe with Slow-Cooked Brisket
- Pork Confit and Split Pea Soup
- Broccoli Cheddar Soup
- Zuppa Toscana
- Chicken Dumpling Soup Recipe
French Onion Soup Recipe
For the Soup:
- 3 ounces of unsalted butter
- 4 each peeled and thickly sliced yellow and white onions
- 1 ½ tablespoons of sugar
- 6 finely minced cloves of garlic
- 2 cups of red wine, I used cabernet sauvignon
- 96 ounces of beef stock
- 2 tablespoons of chopped fresh thyme
- 2 tablespoons of balsamic vinegar
- Kosher salt and fresh cracked pepper to taste
For the Crostini:
- 1 French baguette cut into ½” thick slices
- 1 stick of melted unsalted butter
- Kosher salt and fresh cracked pepper to taste
For the Toppings:
- 1 pound of shredded gruyere cheese
- fresh thyme sprigs for garnish
- In a large rondeau over medium-low heat, melt the butter and caramelize the onions very well (can take up to an hour).
- Halfway through the cooking process add in some sugar to help brown.
- Once caramelized add in the garlic and sweat for 3 to 4 minutes.
- Next, de-glaze with red wine and cook the liquid until it is mostly absorbed into the onions.
- Next, add in the beef stock and simmer for at least 20 minutes.
- Finish with fresh thyme, salt, and pepper and adjust with balsamic vinegar.
- Pour the soup into an oven-safe bowl and top off with a few crostini’s and add on at least ½ cup of gruyere cheese.
- Place the soup on a sheet tray and cook it under the broiler on high heat for 3 to 4 minutes or until the cheese is browned and melted. Garnish with thyme sprigs.