French Onion Soup is one of my favorite things to order at a restaurant. I usually reserve this bowl of warm comfort for restaurants because it’s a soup that takes time and patience to make. But I’ve come to realize that although it is a slow process, it’s still ridiculously simple and inexpensive, so it’s totally worth the effort. I encourage you to make a pot of this incredible French Onion Soup on your next day off while you’re relaxing with a movie or folding some laundry. I think you’ll be glad you did!
What is French Onion Soup?
If you’ve never had the pleasure, French Onion Soup is made with sweet caramelized onions, beef broth, and herbs. The soup is usually topped with a piece of toasted bread and a generous heap of cheese, which are then broiled to perfection. So with every spoonful you get a piece of bread soaked with flavorful broth, melty cheese, and sweet-savory onions. It’s pretty epic.
Don’t Take Shortcuts with Caramelized Onions
It’s so so so so important to properly caramelize the onions when making French Onion Soup (see the step by step photos below for a visual reference). The deep flavor of the caramelized onion is what gives this soup its characteristic flavor. If you take shortcuts with this step it will show in the color and flavor of your soup.
Caramelizing onions, especially this quantity of onions, is a slow process and it takes a lot of time. Like an hour or more. If you stop too soon your soup will be lacking. If you try to go too fast you risk burning the onions not getting that sweet jammy flavor. Just go slow. It’s worth it.
Use Good Broth
The other key to making a really good pot of Classic French Onion Soup is using a really flavorful broth. If you know me then you know I love Better Than Bouillon so I used that to make my broth for this soup. But if you have access to a really good beef stock or bone broth that would also be incredible. Just make sure you use a broth that you know has good flavor.
What Else Can I Add to French Onion Soup?
I made this French Onion Soup recipe as simple as possible while still retaining its rich flavor. But if you want to go above and beyond you can try adding a couple other ingredients.
Wine – Try deglazing the pot (after adding the flour) with about 1/2 cup wine before adding the beef broth. You can use either a dry white wine or a red wine, depending on whether you want your soup to have a lighter touch (white wine) or a richer flavor (red wine).
Sweet Onions – I made my soup with your average everyday yellow onions, but if you want a tad more sweetness you can choose a sweet onion instead.
Brandy or Sherry – A couple tablespoons of brandy or sherry added to your French Onion Soup at the end can brighten the flavors.
Garlic – I didn’t want to muddy the sweet delicate flavor of the onions, but a lot of people do prefer to also add garlic. If adding garlic, mince it up good and sauté it with the caramelized onions for a minute or two just before adding the flour.
Classic French Onion Soup
- 2 Tbsp olive oil ($0.32)
- 3 lbs. yellow onions ($1.19)
- 2 Tbsp butter ($0.28)
- 3 Tbsp flour ($0.03)
- 6 cups beef broth* ($0.78)
- 1/2 tsp dried thyme ($0.05)
- 1 bay leaf ($0.15)
- 1/4 tsp freshly cracked black pepper ($0.02)
- 1 Tbsp Worcestershire sauce ($0.02)
- 5 slices French bread ($1.00)
- 1 cup shredded Swiss or Gruyere cheese ($1.00)
- Slice the onions into ¼-inch thick slices. Add the sliced onions to a large soup pot with olive oil. Cook the onions over medium heat, stirring occasionally. When the onions begin to get a little bit of golden brown color (after about 30-45 minutes), add the butter.
- Continue to cook over medium heat, stirring occasionally until the onions are deeply caramelized (the color of an old penny). This should take about an hour total. If needed, add a couple tablespoons of water to dissolve any browned bits off the bottom to prevent them from burning while the onions continue to cook.
- Once the onions are deep brown and jammy in texture, add the flour. Stir and cook the flour with the caramelized onions for about two minutes more. The flour helps thicken the broth slightly, giving it body.
- Add the beef broth to the pot and stir to dissolve any browned bits off the bottom of the pot. Also add the thyme, bay leaf, pepper, and Worcestershire sauce. Bring the soup up to a simmer, then allow it to simmer for about a half hour. If using a low sodium broth, make sure to taste the soup after simmering and add salt to taste.
- Toward the end of the simmer time, preheat the oven's broiler. Place the bread slices on a baking sheet and place them in the oven on the middle rack. Broil for a few minutes on each side, or just until they are barely golden brown (they will broil more later).
- If you do not have oven safe bowls, top each slice of bread with shredded cheese, then return them to the oven and continue to broil until the cheese is melted and bubbly. Broiling time will vary with each oven, so make sure to watch them closely. This should only take a few minutes. Place one piece of toasted bread with melted cheese on top of each bowl of soup just before serving.
- If you do have oven safe bowls, portion your soup into the bowls, top each one with a piece of lightly toasted bread, then some of the shredded cheese. Place the bowls back on the baking sheet and place everything back in the oven under the broiler. Broil for just a few minutes or until the cheese is melted and bubbly. Serve hot!
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How to Make French Onion Soup – Step by Step Photos
Begin by slicing 3 lbs. yellow onions into thin slices (about ¼-inch thick). Add the sliced onions to a large soup pot with 2 Tbsp olive oil. Cook the onions over medium heat, stirring occasionally.
When the onions begin to get a little golden color (after about 30-45 minutes) add 2 Tbsp butter. Continue to cook over medium heat, stirring occasionally.
The goal is to keep cooking until the onions become deep brown in color and have a jammy texture. If the bottom of the pot begins to brown faster than the onions, just add a couple tablespoons of water to dissolve the browned bits off the bottom and continue to cook. Do not stop when the onions are the color in the photo above. There is still a ways to go!
When the onions are the color of an old penny (see photo above), add 3 Tbsp flour and continue to cook and stir for about two minutes. The flour helps thicken the soup very slightly, just giving it a little extra body.
Finally, add six cups of beef broth to the pot. Stir to dissolve any browned bits off the bottom.
Also add ½ tsp dried thyme, one bay leaf, ¼ tsp freshly cracked pepper, and 1 Tbsp Worcestershire sauce. Bring the soup up to a simmer and let it continue to simmer for about 30 minutes. If you’re using a lower sodium broth, you’ll want to taste the soup and add salt to taste after it simmers.
Toward the end of the simmer time, begin to prepare the cheese toast. Preheat the oven’s broiler. Place slices of French bread on a baking sheet (I only had four soup bowls, so I’m only toasting four pieces right now, but the soup makes about 5 servings). Broil the bread for a few minutes on each side or just until it’s lightly golden brown. It will broil more later with the cheese.
If you have oven-safe bowls, portion the soup into the bowls. If you do not have oven-safe bowls, pile the shredded cheese right onto the toasted bread on the baking sheet, then broil for a few minutes more to melt the cheese. Top each bowl of soup with a cheesy bread slice.
If you do have oven-safe bowls, place the bowls on the baking sheet and add a piece of toasted bread to each bowl, then top with shredded Swiss cheese or Gruyere.
Return the baking sheet with the bowls of soup to the oven and broil for a few minutes more, or until the cheese is melted and the bread is toasty. Every broiler is a little different, and they cook quickly, so keep an eye on them!