Mouthwatering French Onion Soup recipe makes a comforting, classic bowl of soup with caramelized onions in rich soup and crusty bread with melty, delicious cheese! A rustic yet elegant favorite for entertaining! Includes stovetop and slow cooker methods!

French Onion Soup is one of my favorite soups, especially when the temperatures outside drop – even just a little bit.

There’s something so very comforting about breaking through the cheesy, French bread exterior to get to the delicious brothy soup underneath!

While many people consider this soup to be something only served at fancy restaurants, that couldn’t be farther from the truth. A comforting yet elevated soup, this recipe is so simple to make at home and is actually believed to come from humble origins. This recipe is easy to make and great to serve anytime – it is a great comfort food and is perfect for entertaining!

Why You’ll Love This Recipe

• Impressive, yet not expensive – This soup is always impressive and has the reputation of being a “fancy restaurant” soup, making it a great soup to serve when entertaining. But it’s easy to make, and the ingredients are actually not expensive relative to many other ingredients for foods you’d serve when entertaining. Your major investment in this soup is your time to get the onions caramelized, but it is oh-so worth it!
• Full of rich flavor – The caramelized onions, buttery rich broth, and cheesy, crusty bread make this a delicious favorite all your guests will love!
• Easy to make by two methods – You can make this scrumptious soup in your Dutch oven or put all the ingredients in your slow cooker and allow it time to bubble away for you to enjoy later! Either way is easy to do!

How to Make French Onion Soup Recipe

It has always been one of those soups that I would look forward to having at restaurants, but I didn’t know how to make it at home when we first married.

It wasn’t until our third Christmas together that I tried to make it. We were hosting the soup course of a Christmas progressive dinner, and my husband requested it. It turned out perfectly and continues to be a go-to recipe for me.

French Onion Soup Ingredients

French onion soup includes a few classic ingredients for its signature flavor and presentation. You’ll need:

• Sweet onions: – See “Tips – The Best Onions for French Onion Soup” to follow. (If you are not able to find sweet onions, use yellow onions as your next choice). Make sure to slice your onions for this soup thinly. The thin slices are better for caramelizing, adding a sweet, delicious flavor to this recipe.
• Butter: It helps to brown the onions and adds flavor to the soup.
• Salt: Helps the onions to release their juices and balances the flavor.
• Olive oil: The onions cook with a bit of olive oil.
• Garlic: A clove of minced garlic adds flavor.
• Beef stock or broth: French onion soup is a broth-based soup, and I prefer to use a mixture of beef and chicken stock or broth in my soup. Since this is a broth-based soup, taste the broth before you use it, especially if you’ve never used the brand before. You want to make sure it tastes good as it is a big part of the flavor of your soup.
• Chicken stock or broth: See the note above under beef stock.
• French bread: Lightly toasted and served on top of the soup. Yum!
• Cheeses: Grated Gruyere and Parmesan cheese top the soup.

Step-by-Step Instructions

Caramelize the onions.

Slice onions thinly. Add onions, salt, and butter to a Dutch oven set over low heat. Stir occasionally until the onions have cooked down and are a caramel color, about 45 minutes to an hour. Caramelizing onions is important to the recipe and takes a bit of time, but the result is amazing depth of flavor the the best french onion soup!

Cook the garlic.

Add garlic and cook until fragrant, about 1 minute.

Stir in stock and simmer.

Then, add the beef and chicken stock and stir. Cover and let simmer for 30 minutes.

Scoop into bowls.

Ladle the soup into individual, oven-proof soup bowls.

Top with bread, cheese, and bake.

Top with toasted bread and the cheeses. Then place on a lined baking sheet and under the broiler in the oven until the cheeses have melted and browned lightly, about 8 minutes.

Recipe Tip – The Best Onions for French Onion Soup

The onion is such an important ingredient in this soup. Different onions can change the overall taste of your soup, so some types of onion make a better soup than others. While it may be a personal preference, I have tested various types of onions in my recipe through the years – cooking times, amount of caramelization, and more, to find the recipe that appeals the most – and this is it!

I’ve tested three varieties for my French Onion Soup recipe:

• Sweet Onions – sweet onions, such as Vidalia, give the soup a mildly sweet flavor without a bitter aftertaste. 
• Yellow Onions – yellow onions give the soup a lot of flavor with some bitterness.
• Red Onions – red onions give the soup a strong flavor without much sweetness.

I prefer and highly suggest using sweet onions as I believe it makes the best onion for French Onion Soup. If you can not find sweet onions, yellow onions are the next best one to use.

How to Make Slow Cooker French Onion Soup

I love to make my French Onion Soup in crockpot! It is a simple process that leaves you without babysitting the onions as they caramelize or waiting for the soup to simmer.

Step-by-Step Instructions for Slow Cooker French Onion Soup

Caramelize Onions in Slow Cooker: Add your thinly sliced onions to the slow cooker, along with butter and salt. Pop the lid onto your slow cooker and set it on low heat for 10 hours. This is perfect for doing overnight so that you are ready for step two of your soup in the morning!

Make the soup: Once your onions have caramelized in your slow cooker, you are ready to move to step two with your Slow Cooker French Onion Soup! Add garlic, beef stock, and chicken stock. Stir well to combine and cook on low setting for 8 hours. 

Broil and serve. When ready to serve, ladle soup into oven-proof bowls and top with bread and cheeses. Place on a lined baking sheet and under the broiler in the oven until the cheeses have melted and browned lightly, about 8 minutes. 

Here’s my French Onion Soup recipe. I hope you love it as much as we do!

Enjoy!
Robyn xo