Today we’re making the coziest Winter dish, homemade French Onion Soup with O-Live & Co. toasted baguette and lots of sharp gruyere cheese. 

This post was sponsored by O-Live & Co. All thoughts and opinions are originally my own. 

A bowl of French Onion Soup next to glasses of wine

A classic French recipe

If you love French cuisine, chances are you know and love French onion soup. This traditional recipe originated in Paris, where onions grew easily and were considered food for poor people.

Today, it’s a popular dish served in restaurants around the world. Known and loved for its rich onion forward broth and cheesy, crunchy bread topping. 

I love making this homemade French onion soup during the cold winter months and enjoying a warm bowl next to a hot fire. 

A hand pouring olive oil into a pot full of onions

What you’ll need

To start off your French onion soup you’ll need a few pounds of onions, butter and some good quality olive oil. 

Today I’m partnering with my friends at O-Live & Co. and using their Everyday olive oil to caramelize the onions and toast the crostini topping. Their oil has won multiple awards and scored 97/100 points in the Flos Olei rankings, the world’s most prominent olive oil ranking. This makes it the perfect oil to pair with butter in a classic French recipe like this. 

Once your onions have had enough time to caramelize with the oil and butter, it’s time to add some white wine, herbs and a splash of balsamic vinegar for added flavor and acidity. 

From there, a generous pour of beef stock gets added and the whole thing gets turned up and brought to a boil. Continue to simmer your soup for a good 25 minutes. 

While your broth is simmering, it’s time to make some crostini from a baguette and grate the gruyere cheese. 

A torch melting cheese over a bowl of French Onion Soup

Picking the right onions

There are a few different kinds of onions that will work in this recipe… but I recommend using sweet onions.

I would say you can get away with yellow onions, but sweet onions take the depth of flavor in this homemade French onion soup to the next level. Sliced the right way, caramelized with butter and olive oil, they are truly a dream come true. 

And for anyone wondering… purple onions are a hard no. 

A bowl of sweet onions

Slicing your onions

Slicing 5 onions for this recipe is already a difficult task, don’t get me wrong. I am well aware that tears will be shed. I lost track of how many tears were shed in the countless hours I spent testing this recipe. 

This soup is 100% worth it. 

So even though I know slicing the onions is the last thing you want to slow down and take your time on, I’m telling you this part is important. 

Unlike many vegetable based soups, this one doesn’t get pureed or blended. Meaning, your end result will have onion slices in it. Meaning, your knife skills matter here.

Too thick onions will result in a chunky soup, too thin ones will result in mushy onions. 

So take a few extra minutes to make sure your onions are sliced uniformly. Consistently. Aim for ¼ inch in thickness.  

Two hands holding a bowl of French Onion Soup

Vegetarian, vegan & gluten free substitutions 

While this soup is usually made with beef broth, lots of butter and cheese, I’ve got a couple tricks up my sleeve to help make this a dish everyone can enjoy:

  • Vegetarian substitutions – swap the beef broth for vegetable broth
  • Gluten free substitutions – swap the baguette for a gluten free baguette 
  • Vegan substitutions – swap the butter for olive oil, swap the beef broth for vegetable broth, swap the cheese for vegan cheese or a light sprinkle of nutritional yeast

Other soup recipes I love 

If you’re new here, you need to try these other soup recipes:

A spoon scooping up some French Onion Soup

Happy cooking!

Salima written in cursive
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A bowl of French Onion Soup next to glasses of wine

Homemade French Onion Soup with O-Live & Co.

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  • Author: Salima Benkhalti
  • Prep Time: 15 minutes
  • Cook Time: 1 hour
  • Total Time: 1 hour
  • Yield: 34 servings 1x
  • Category: French, Soup, Dinner
  • Method: Boiled
  • Cuisine: French
  • Diet: Vegetarian


  • 4 sweet onions
  • 2 tbsp O-Live & Co. Everyday Olive Oil
  • 2 tbsp butter
  • 2 tsp salt
  • 1 tbsp flour (I used gluten free flour) 
  • 1 cup white wine 
  • 2 tsp balsamic vinegar
  • 6 cups beef stock
  • 3 bay leafs 
  • 4 sprigs thyme (dry thyme works too) 
  • 2 tsp pepper
  • 1 tbsp O-Live & Co. Everyday Olive Oil
  • 1 baguette (I used a gluten free baguette), sliced
  • 2 cups grated Gruyere cheese
  • Additional sprigs of thyme to garnish with 


  • Begin by peeling and thinly chopping onions (see picture). In a heavy bottomed stock pot melt the butter and olive oil over medium heat. 
  • Add in onions and salt and caramelize for 25-30 minutes over medium high heat, stirring every 3-4 minutes until they are brown and soft in texture. Be careful not to overmix as this can result in mushy onions. 
  • Once the onions are caramelized, sprinkle in flour, cook off for a minute then add wine and simmer until the wine reduces by half. Stir in balsamic vinegar, thyme, bay leaf and beef stock and bring to a boil over high heat. Lower to a simmer for an additional 25-30 minutes minutes. 
  • While the soup is simmering, slice and brush the baguette slices with more olive oil. Toast them lightly and grate the cheese. 
  • Taste the broth and add salt and pepper to your preferred taste. Spoon soup into small oven safe ramekins and top with a slice of baguette and a generous sprinkle of cheese. Broil for 4-5 minutes or until the cheese is golden brown and bubbly. Top with additional fresh thyme and enjoy!